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PARIS  UNIVERSAL  EXPOSITION,  1889. 


AND 


ARCHITECTURE, 


ltY 


WILLIAM  WATSON,  Ph.  D., 

Fellow  of  the  American  Academy  of  Arts  and  Sciences;  member  of  the  Xalional  Academy 
of  Cherbourg,  of  the  French  Society  of  Civil  Engineers,  of  the  Prussian  Society  of 
Industrial  Engineers,  of  the  American  Society  of  Civil  Engineers,  of  the 
American  Society  of  Mechanical  Engineers;  late  17.  S.  Commis- 
sioner to  the  Vienna  Exposition;  member  of  the  Interna- 
tional Jury  at  the  Paris  Exposition  of  1S7S,  etc. 


WASHINGTON: 

GOVERNMENT  PRINTING  OFFICE. 

1892. 


ERRATA. 


Page. 

Sect. 

Line. 

547 

36  for  Fontaine  put  Fontaine’s. 

551 

23  for  Nougier  put  Nouguier. 

551 

25  for  Contemin  put  Contamin. 

551 

25  for  Groclaude  put  Grosclaude. 

555 

4 

21  for  Boulonge  put  Boulogne. 

555 

5 

9,  10  for  with  a border  0.010  meters  th 
meter  thick. 

566 

36 

3 for  Seine  put  same. 

566 

36 

4 for  brace  put  braces. 

570 

41 

7 for  apron  put  flooring. 

571 

5 for  apron  put  flooring. 

592 

57 

14  for  by  put  from. 

627 

110 

2 for  that  put  this. 

672 

173 

7 after  tide  put  the  gates  are  open  and. 

672 

173 

7 after  vessels  put  of  any  length. 

722 

234 

12  for  adopted  put  followed. 

741 

14  for  165  put  151. 

767 

286 

20  for  allows  put  allow. 

809 

328 

2 after  of  put  the  upright  cut  by. 

846 

8 for  cars  put  ears. 

883 

412 

2 for  there  put  three. 

Plate 

IV. 

for  Reynard  put  Reguard. 

UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


ILLUSTEATIONS 

IN  THE 

REPORT  ON  CIVIL  ENGINEERING,  PUBLIC  WORKS,  AND  ARCHITECTURE. 


Plate  I.  View  of  the  hydraulic  canal  lift  at  Les  Fontinettes 552 

Plate  II.  View  of  the  trough  basin  at  Les  Fontinettes 554 


Plate  III.  Pumping  machinery  at  Les  Fontinettes 558 

Plate  IV.  Model  of  Poses  dam ; by  Regnard  Brothers,  Paris 592 

Plate  V.  Construction  of  the  quays  at  Calais ; process  of  sinking  the 

piles  by  means  of  water  jets 674 

Plate  VI.  Construction  of  the  outer  harbor  quays  at  Calais ; process 

of  sinking  the  foundation  curbs  by  means  of  water  jets.  678 

Plate  VII.  Port  of  Havre;  lock  gates  of  the  Bellot  basin 696 

Plate  VIII.  Framework  of  the  iron  dock  sheds  at  Havre 700 

Plate  IX.  The  lower  portion  of  the  arch  of  the  Garabit  viaduct 762 

Plate  X.  Garabit  viaduct  during  the  process  of  erection 766 

Plate  XI.  Iron  framework  of  a Paris  store  (the  Magazin  duPrintemps)  804 

Plate  XII.  The  Eiffel  Tower;  iron  caissons,  used  with  compressed  air  in 

building  the  foundation  of  a pier 812 

Plate  XIII.  The  Eiffel  Tower;  view1  of  a pier  with  its  inclosing  walls. . 814 

Plate  XIV.  The  Eiffel  Tower;  new  scaffolding,  45  meters  high,  for  unit- 
ing the  isolated  piers 818 

Plate  XV.  The  Eiffel  Tower;  details  of  the  ironwork  of  the  structure.  820 

Plate  XVI.  The  Eiffel  Tower;  the  erecting  crane  used  above  the  second 

story 824 

Plate  XVII.  The  first  story  of  the  Eiffel  Tower 826 

Plate  XVIII.  Complete  view  of  the  Eiffel  Tower 830 

Plate  XIX.  View  of  Machinery  Hall,  showing  the  end  truss  girder  and 

the  gables 856 

Plato  XX.  Interior  view  of  Machinery  Hall 856 

Plates  XXI  and  XXII.  Two  groups  of  figures  supporting  the  lintel  of  Ma- 
chinery Hall;  one  by  M.  Barrias,  representing 
electricity;  the  other  by  M.  Chapu,  personifying 
steam 862 

Hydraulic  canal  lift  at  Les  Fontinettes. 

Figure  1.  Plan  of  the  hydraulic  lift  at  Les  Fontinettes 553 

Figure  2.  Longitudinal  section  along  the  axis  of  the  trough 554 

Figure  3.  Cross  section  through  the  transverse  axis  of  the  lift 556 

Movable  dam  at  Suresnes  on  the  Seine. 

Figure  4.  Map  and  general  plan  of  the  dam 565 


ILLUSTRATIONS. 


XIII 


Civil  Engineering,  Public  Works,  and  Architecture— Continued.  paKe. 

Figures  5-7.  Movable  frame  of  the  Navigable  Pass;  elevation  and  sections  567 
Figure  8.  Movable  frame,  with  its  panels 568 

The  Marly  dam  on  the  Seine. 

Figure  9.  Fixed  frame  used  in  the  Marly  dam 571 

Figure  10.  Method  of  anchoring  the  frame 571 

New  river  lock  at  Bougival. 

Figure  11.  Map  showing  the  situation  of  the  lock 573 

Figure  12.  Machinery  house  and  accumulator;  longitudinal  section 575 

Figure  13.  Machinery  house  and  accumulator;  horizontal  section 576 

Figure  14.  Machinery  house  ; transverse  section 577 

Apparatus  for  operating  the  lock  sluices  by  hydraulic  power  alone. 

Figures  15  and  16.  Vertical  section  and  elevation 578 

Figure  17-18.  Plan  and  section  of  the  sluices 579 

Combined  apparatus  for  operating  the  lock  sluices  either  by  hand  or  by  hydraulic  poiver. 

Figures  19-23.  Elevation,  plan  and  sections 580 

Figures  24  and  25.  Valve  chest;  vertical  sections 581 

Hydraulic  apparatus  for  opening  and  closing  the  lock  gates. 

Figures  26  and  27.  Longitudinal  section  and  plan 582 

Figures  28  and  29.  Sections 583 

Hydraulic  capstan. 

Figures  30  and  81.  Sections 585 

Figure  32.  Plan  (cover  removed)  586 

Figures  33  and  34.  Elevation  and  sections 587 

Movable  dam  at  Poses  on  the  Seine. 

The  uprights  and  curtains. 

Figure  35.  Longitudinal  section  in  front  of  the  uprights 589 

Figure  36.  Transverse  section 590 

Figures  37  and  38.  Hoisting  windlass 590 

Figure  39.  Section  of  the  chain  stop 590 

Figures  40  and  41.  Details  of  the  curtain  hinges  and  shoe 591 

Figure  42.  Transverse  section 593 

Figures  43  and  44.  Sections  of  members 593 

Figure  45.  Plan  and  horizontal  section  of  the  bridge  at  different  heights.  594 

Figures  46  and  47.  Sections  of  members 594 

Figure  48.  Upstream  elevation  of  the  intermediate  girder 595 

Figure  49.  Map  showing  position  of  the  new  movable  dam  at  Poses 597 

Figure  50.  Elevation  and  section  of  the  abutment  on  the  left  bank,  with 

the  anchorage  for  the  foundations 598 

Figure  51.  View  of  the  dam  from  below 599 

Figure  52.  View  of  the  dam  from  above;  raising  a frame 601 

Figure  53.  View  from  below;  rolling  a curtain 601 

Figures  54  and  55.  Mode  of  suspending  the  frames  (Port-Mort  Dam)  ....  602 

Movable  dam  at  Villez. 

Figure  56.  General  view  of  the  dam 607 

Figure  57.  Lowering  the  frames  at  Villez  Dam 608 

Figures  58  and  59.  Windlass  for  hoisting  and  lowering  the  curtains,  and 

the  mode  of  unshipping  and  transporting  them ....  609 

Movable  fish  way  at  Port-Mort. 

Figure  60.  View  of  the  fish  way 611 


XIV 


ILLUSTRATIONS. 


Civil  Engineering,  Public  Works,  and  Architecture — Continued. 

Torcy-Neuf  reservoir  for  the  Central  Canal. 

Page. 

Figure  61.  Map  of  the  reservoir 613 

Figure  62.  Cross  section  of  the  dike,  the  water  tower  and  the  culvert. . 615 

Figures  63-65.  Section,  elevation,  and  details  of  the  sluice 617 

Figures  66-69.  Elevation  and  vertical  and  horizontal  sections  of  the  guard 

gate,  with  details 618 

New  high  lift  locks  on  the  Central  Canal. 

Figures  70-74.  Sections  of  a high-lift  lock 620 

Figures  75  and  76.  Half  cross  sections  through  the  axes  of  the  sluice  pits.  621 

Figure  77.  Fontaine’s  cylindrical  sluice  ...  622 

Figures  78  and  79.  Elevation  and  section  of  the  lowei  gates  of  the  lock.  . 623 

Cable  towage  for  boats  on  canals  and  rivers. 

Figure  80.  Details  of  the  pulley  and  the  rope  connections 626 

Figures  81  and  82.  Elevation  and  plan  of  a double  pulley  for  a concave 

angle 628 

Figure  83.  Single  pulley  for  concave  angles 629 

Figures  84  and  85.  Hooking-on  and  casting-off  grip 629 

Figure  86.  The  grip,  with  the  tow  rope 630 

Towage  by  a submerged  chain  and  a fireless  engine. 

Figures  87  and  88.  Plan  and  sections  of  the  chain  towboats 633 

System  for  supplying  the  canal  from  the  Marne  to  the  Rhine. 

Figure  89.  Vertical  section  through  the  pumping  station  at  Pierre-la 

Treiche 636 

Figure  90.  Plan  of  the  same 637 

Oscillating  bridge  over  the  Dames  Canal  lock. 

Figure  91.  Diagram  showing  the  action  of  the  bridge 638 

Balanced  gates  on  the  Rhone  and  Cette  Canal. 

Figure  92.  Segmental  balance  gate  at  Croisee-du-Lez 640 

Braye-en-Laonnois  Tunnel. 

Figure  93.  Geological  section 643 

Figure  94.  Sections  showing  details  of  the  construction  of  the  tunnel...  644 

Figures  95  and  96.  Sections  of  the  air  lock 645 

Figure  97.  The  method  adopted  for  ventilating  the  tunnel 647 

Embankment  ivorks  for  the  improvement  of  the  tidal  Seine. 

Figure  98.  Map  of  the  tidal  Seine 650 

Figures  99-101.  Schemes  A,  B,  and  B2,  for  training  the  river  through  its 

tidal  estuary 661 

Figure  102.  Scheme  C 662 

Figures  103  and  104.  Schemes  D and  D bis 663 

Figure  105.  Scheme  E 664 

Figure  106.  Scheme  E bis ...  665 

Figure  107.  Scheme  F 666 

Calais  Harbor  works. 

Figure  108.  Plan  of  Calais  Harbor 671 

Figure  109.  Cross  sections  of  the  dike  and  quays 675 


ILLUSTRATIONS. 


XV 


Civil  Engineering,  Public  Works,  and  Architecture— Continued.  paKe. 

Figure  110.  Cross  section  on  a larger  scale  of  the  Northeast  quay 070 

Figures  111-113.  Section  and  plans  of  a curb 078 

Figure  114.  Arrangements  of  water  jets  for  lowering  a curb 078 

Figure  115.  Section  of  a finished  curb 079 

Figure  110.  Method  of  cementing  two  consecutive  blocks  together 079 

Figure  117.  Profile  of  the  eastern  quay  wall  of  the  eastern  dock 083 

New  outer  harbor  at  Boulogne. 

Figure  118.  Map  of  the  port  of  Boulogne 688 

Figure  119.  General  view  of  the  new  deep-water  harbor 690 

Figure  120.  Cross  section  of  the  parallel  dike  b 691 

Port  of  Havre — Bellot  lock  and  trail  wave-breaker. 

Figure  121.  Transverse  section  of  the  Bellot  lock 694 

Figures  122  and  123.  Elevation  and  plan  of  the  revolving  bridge  over 

the  lock 695 

Figures  124  and  125.  Elevation  and  section  of  a leaf  of  the  lock  gates  . . . 096 

Figure  126.  Lifting  press  and  wedge  of  the  revolving  bridge 698 

Figure  127.  Apparatus  for  operating  the  lock  gates ; elevation  and  plan 

of  a leaf 698 

Figure  128.  Complete  plan  of  the  lock  gates  with  the  operating  appara- 
tus   699 

Figure  129.  Iron  wave-breaker 701 

Canal  from  Havre  to  Tancarville. 

Figures  130-133.  Elevation,  half  plan,  and  sections  of  the  Tancarville 

lock  gates 703 


Slipway  at  Rouen  for  the  repair  of  ships. 

Figure  134.  General  plan  of  the  slipway 705 

Figure  135.  Cross  section 706 

Figure  136.  Hauling  machinery ...  706 

Figure  137.  Method  of  attaching  the  compensating  cable  to  the  cradle..  707 
Figure  138.  Details  of  the  shores 708 


Port  of  Honfleur. 

Figure  139.  Plan  of  the  port  of  Honfleur  and  the  sluicing  basin  709 

Figures  140  and  141.  Apparatus  for  closing  the  sluicing  lock  at  Honfleur.  710 

Figure  142.  The  feeding-weir  gates  of  the  sluicing  basin 713 

Figure  143.  Siphonage  between  the  basins;  sections  of  the  siphons 716 

Traversing  bridge  at  St.  Malo  St.  Servan. 

Figure  144.  Section  of  the  bridge,  and  details 718 

Figure  145.  Diagram  of  the  operation  of  the  recuperator 719 

Figure  146.  Vertical  section  and  plan  of  the  recuperator 719 

Figure  147.  Horizontal  section  of  the  recuperator  press 720 

Hydraulic  works  and  pneumatic  foundations  at  Genoa. 

Figure  148.  Transverse  section  of  the  movable  caissons  used  for  drilling 

the  rock  for  the  purpose  of  submarine  blasting 727 

Figure  149.  Transverse  section  of  the  movable  caissons  used  in  laying 

the  masonry  under  water 727 

Figure  150.  Elevation  and  longitudinal  section  of  the  same 728 


XVI 


ILLUSTRATIONS. 


Civil  Engineering,  Public  Works,  and  Architecture — Continued.  page. 

Figures  151-156.  Details  of  the  excavation  lock 729 

Figure  157.  Great  floating  caisson  used  in  laying  the  flooring  of  Basin 

No.  2;  transvei'se  section 730 

Figures  158  and  159.  Positions  of  the  caissons,  with  and  without  ballast.  732 

Figures  160  and  161.  Caissons  at  work 732 

Figure  162.  Method  of  laying  the  flooring  of  a basin 734 

Figure  163.  Quay  walls  in  arcades,  Quai  des  Graces;  longitudinal  section . 734 

Figure  164.  Details  of  the  iron  centers  735 

Port  of  Rochelle — Foundations  of  jetties  at  La  Pallice. 

Figure  165.  Plan  of  the  outer  harbor  of  La  Pallice 736 

Figure  166.  Caisson  raised  from  the  block 737 

Figures  167  and  168.  Caisson  resting  on  jacks 739 

Figure  169.  Method  of  closing  the  space  between  the  blocks 742 

Figures  170-172.  Sections  showing  the  wralls  under  the  panels  and  the 

method  of  holding  the  panels 743 

The  new  steel  bridge  at  Rouen. 

Figures  173  and  174.  Elevation  and  plan 746 

Figure  175.  Upstream  elevation  of  Pier  No.  2 747 

Suspension  bridge  at  Tonnay-Charente. 

Figure  176.  General  view  of  the  bridge 749 

Figures  177  and  178.  Method  of  attaching  the  cable  and  suspension  rods.  750 
Figure  179.  M.  Anodin’s  alternately  twisted  cable 751 


The  lifting  bridge  at  La  Villette,  Paris. 

Figure  180.  Elevation 752 

Figure  181.  Transverse  section 753 

Figure  182.  System  of  guiding  the  bridge 754 

Figure  183.  Details  of  a press  and  the  superstructure 754 

Figure  184.  Three-way  cock 755 

The  Garabit  viaduct. 

Figure  185.  General  view  of  the  Garabit  viaduct 757 

Figure  186.  Elevation  of  the  central  portion,  and  sections  of  the  members.  760 

Figures  187  and  188.  Wind  bracing 760 

Figure  189.  Elevations  of  pier,  and  cross  sections  of  members 762 

Figure  190.  Erection  of  the  iron  arch;  beginning  of  the  process  of  erec- 
tion   764 

Figure  191.  Appearance  in  an  advanced  stage  of  erection 765 

Gour-JSoir  viaduct. 

Figure  192.  General  view  of  the  structure 768 

Viaduct  over  the  river  Tardes. 

Figures  193  and  194.  Elevation  and  plan  of  the  viaduct 770 


Consolidation  of  the  side  slopes  of  the  railway  cutting  at  La  Plante. 


Figure  195.  View  of  the  slopes  after  the  completion  of  the  work 772 

Tunnel  through  Cabres  Pass. 

Figure  196.  Half  sections  of  the  tunnel 774 

Figure  197.  Center  used  in  the  construction •»  774 


ILLUSTRATIONS. 


XVII 


Civil  Engineering,  Public  Works,  and  Architecture— Continued. 

Cubzac  Bridge  over  the  Dordogne. 

Paere. 

Figure  198.  Partial  elevation  of  the  Cubzac  Bridge  and  viaduct 776 

Figure  199.  Elevation  of  a pier  of  the  viaduct  of  approach  (left  bank) . . . 777 

Figure  200.  Elevation  of  an  abutment  777 

Figure  201.  Elevation  of  an  iron  pier 778 

Construction  of  the  Custelet,  the  Laveur,  and  the  Antoinette  Bridges. 

Figure  202.  Elevation  of  the  Castelet  Bridge 782 

Figure  203.  View  of  the  Antoinette  Bridge  and  section  of  the  viaduct  . . . 783 

Figure  204.  Elevation  of  the  Laveur  Bridge 783 

Figure  205.  Center  of  Castelet  Bridge ; elevation  of  a truss 785 

Figure  206.  Antoinette  Bridge ; elevation  of  a truss  786 

Figure  207.  Center  of  the  Laveur  Bridge 787 

Figures  208  and  209.  Supports  for  the  rings 788 

The  Ceret  Bridge. 

Figure  210.  Elevation,  half  plan,  and  half  horizontal  section 791 

The  crossing  of  the  Garonne  at  Marmande. 

Figure  211.  Plan  of  the  submersible  plain  of  the  Garonne  near  Marmande.  792 

Figure  212.  Longitudinal  section  of  the  roadway  across  the  plain 793 

Figures  213-219.  Masonry  caissons  used  in  building  the  foundations  of 

the  viaducts 795 

Bridge  over  the  Gave  D'Oloron  and  the  Gravona  Bridge. 

Figure  220.  View  of  the  bridge  over  the  Gave  D'Oloron 797 

Figure  221.  View  of  the  Gravona  Bridge  (railroad  from  Ajaccio  to  Cortej  799 

Specimens  of  iron  construction  in  Paris. 

Figure  222.  Pneumatic  apparatus  used  for  the  foundations  of  the  Mag- 

azin  du  Printemps 802 

Figures  223-225.  Transverse  sections  of  the  pillars 804 

The  Eiffel  Tower. 

Figure  226.  Diagram  of  the  resistance  of  the  simple  lattice 807 

Figure  227.  Diagram  of  the  stability  of  the  Eiffel  Tower  when  exposed  to 

the  pressure  of  the  wind ; two  cases 807 

Figure  228.  General  plan  of  the  foundations 810 

Figure  229.  Longitudinal  section  of  the  Champs  de  Mars  at  piers  1 and  2.  811 

Figure  230.  Longitudinal  and  transverse  sections  of  the  iron  caisson 811 

Figure  231.  View  and  section  of  a caisson  showing  the  underground  work 

and  the  shafts  for  the  men  and  the  materials 812 

Figure  232.  Plan  and  section  of  pier  No.  1 814 

Figure  233.  Anchorage  of  the  foundations 815 

Figure  234.  Erection  of  the  tower;  appearance  in  August,  1887 816 

Figure  235.  The  erecting  cranes  used  in  the  construction  of  the  first  and 

second  stories 819 

Figure  236.  View  of  the  first  story 820 

Figure  237.  Details  of  the  hydraulic  jack 821 

Figure  238.  Operation  of  lifting  one  standard  of  the  tower  by  an  hydraulic 

jack 822 

Figure  239.  Arrangement  of  the  crane  for  constructing  the  tower  above 

the  second  story 823 

Figure  240.  Campanile  of  the  tower 825 

Figures  241  and  242.  Verification  of  the  verticality  of  the  tower 828 

H.  Ex.  410 — VOL  III II 


XVIII 


ILLUSTRATIONS. 


Civil  Engineering,  Public  Works,  and  Architecture— Continued. 

The  Machinery  Hall. 

Page. 

Figure  243.  General  plan  of  the  foundations 837 

Figure  244.  Geological  section  of  the  Champs  de  Mars 838 

Figures  243  and  246.  Foundation  for  a truss  girder 839 

Figure  247.  Elevation  of  one  of  the  principal  truss  girders 840 

Figures  248-231.  Sections  of  the  great  truss  girders 841 

Figures  232-254.  Sections  of  the  girders 842 

Figures  255-257.  Purlin  ; elevation  and  sections  ' 844 

Figures  258-261.  Rafter,  rafter  end,  and  sections  A and  B 845 

Figure  262.  Section  of  rafter 846 

Figure  263.  Method  of  erecting  a great  truss  girder  employed  by  the  Fi  ves- 

Lille  Co 847 

Figures  264  and  265.  Elevation  and  plan  of  the  foot  of  a great  truss 849 

Figure  266.  Special  arrangement  of  the  pulleys  for  lifting  the  foot  of  the 

girder  ...  •. 850 

Figure  267.  Scheme  adopted  by  the  Fives-Lille  Co.  for  erecting  the  rafters 

and  purlins 850 

Figures  268  and  269.  Method  of  holding  and  rolling  the  purlins  on  the 

girder? 852 

Figure  270.  Lowering  a purlin 852 

Figure  271.  Scaffolding  for  erecting  the  great  truss  girders ; Cail  & Co. . 853 

Figure  272.  Upper  platform  of  the  rolling  scaffolding 854 

Figure  273.  Cail  & Co.’s  method  of  erecting  the  purlins 855 

Figure  274.  Cupola  of  the  Machinery  Hall  vestibule ; transverse  section . . 857 

Figures  275  and  276.  Scaffoldings  used  in  erecting  the  vestibule  of  Ma- 
chinery Hall 858 

Figure  277.  Longitudinal  fagade  of  the  side  galleries 859 

Figure  278.  Transverse  section  through  the  crown  of  the  arch 860 

Figure  279.  Lateral  view  of  the  side  galleries  from  the  principal  nave. ..  861 

Light-houses. 

Figures  280  and  281.  Section  and  elevation  of  the  Planier  Light-house..  . 865 

Figure  282.  Iron  light-house  at  Port  Vendres 868 

Figure  283.  Lodging  room  of  Port  Vendres  Light-house 869 

Figure  284.  Hyper-radiant  apparatus  for  the  new  light-house  at  Cape 

Antifer,  near  Havre 871 

Figures  285  and  286.  Apparatus  lighted  with  petroleum  oil 873 

Figure  287.  Regulating  brake  and  indicator  of  stoppage 874 

Figures  288  and  289.  Lamp  maintaining  the  oil  at  a constant  level 876 

Figures  290  and  291.  Bifocal  apparatus  for  an  electric  light-house 877 

Figures  292-294.  Electric  regulators  and  indicators 880 

Figure  295.  Light -house  at  Belle  Isle,  with  acoustic  apparatus 882 

Figure  296.  Apparatus  for  lighting  beacon  towers  with  gasoline 884 

Graphic  method  of  quadrature.  By  M.  Ed.  Collignon. 

Figure  297.  Application  to  trapezoids 885 

Figure  298.  Application  to  trapezoids 886 

Figure  299.  Transformation  of  rectangles 887 

Figure  300.  Quadrature  of  curves 887 


REPORT 


ox 


BY 


WILLIAM  WATSON,  Ph.  D., 

Fellow  of  the  American  Academy  of  Arts  and  Sciences;  member  of  the  National 
Academy,  Cherbourg;  of  the  French  Society  of  Civil  Engineers;  of  the 
Prussian  Society  of  Industrial  Engineers;  of  the  American  Society 
of  Mechanical  Engineers ; of  the  American  Society  of  Civil 
Engineers;  late  U.  S.  Commissioner  to  the  Vienna 
Exposition;  member  of  the  International  Jury 
of  the  Paris  Exposition  of  187S,  etc. 


543 


WEIGHTS  AND  MEASURES. 


CONVERSION  OF  FRENCH  WEIGHTS  AND  MEASURES  INTO  THEIR  ENGLISH  EQUIVALENTS. 

Measurements  of  length. 


French. 

British. 

Millimeter . . 

Meters. 

0.001 

0.01 

0.1 

3. 937  inches. 

1 

1,000 

0. 62138  mile. 

Measurements  of  surface. 


French. 

British. 

Square  meters. 
0.000001 
0.0001 

1 

10,000 

0.00155  square  inch. 

0. 155006  square  inch. 

10.7643  square  feet. 

107,643  square  feet  =2.47114  acres. 

Measures  of  volume. 


French. 

British. 

Cubic  meter. 
0.000000001 
1 

0‘.  0000610271  cubic  inch. 
35. 3166  cubic  feet. 

Measures  of  capacity. 

French. 

British. 

1 liter  . . 

. | 61. 0266  cubic  inches. . 

0.220215  gallon. 

Weight. 


French.  , 

British. 

1 kilogram. 

2,20«i2  pounds. 

1 

Measure  of  work. — 1 kilogramineter  =7.23314  foot-pounds. 
Money.— 1 franc=$0.194  gold. 

H.  Ex.  410 — vol  iii 35 


545 


TABLE  OF  CONTENTS. 


Page. 

Introduction 551 

PART  I.— RIVERS  AND  CANALS. 

Chapter  I.— Hydraulic  canal  lifts  at  Les  Fontinettes  and  La  Lou- 

viere 552 

Les  Fontinettes  lift — Introduction — Principle  of  the  lift — Description 
of  the  works — The  troughs — The  pistons — The  ] tresses — The  guides — 

The  machinery  (pistons  and  pumps) — Method  of  working — Time 
required  for  an  up  and  down  motion — The  towers — Method  of 
erecting  the  presses  and  pistons — Cost — Summary — Acknowledg- 
ment. 

La  Louviere  lift — General  remarks — The  presses — Tests  of  the  mate- 
rials— Precautions  against  freezing — Improvements  proposed — 

Cost — Summary, 


Chapter  II. — The  movable  dam  at  Suresnes  on  the  Seine 564 

General  description — Frames — Panels — Cost. 

Chapter  III. — Marly  dam  on  the  Seine 570 

General  description — Flooring — Frames — Panels — Cost. 

Chapter  IV.— The  new  lock  at  Bougival  and  its  hydraulic  oper- 
ating appliances 572 

Location — Motive  power — New  locks — Gates — Hydraulic  machinery — 
Protection  against  frosts — Operating  apparatus — Hydraulic  cap- 
stans— Advantages  of  the  system — Cost  —Conclusion. 

Chapter  V.— New  movable  dam  at  Poses  on  the  Seine 588 


Introduction — The  curtains — The  suspending  bridge — The  hoisting 


bridge — New  principles — Depth  of  foundation — The  flooring — The 
frames,  and  their  method  of  suspension — Footbridge — Method  of 
working — Construction — Cost. 

Chapter  VI. — Villez  movable  dam  on  the  Seine 606 

System  of  closing — Frames — Method  of  opening. 

Chapter  VII.— Movable  fish  way  erected  at  Port-Mort  Dam  on 

the  Seine 610 

Chapter  VIII. — Torcy-Neuf  Reservoir  for  feeding  the  Central 

Canal 612 

Generalities — The  dike — The  gate  tower — Sluices — Guard  lock — Cost. 

Chapter  IX. — The  new  high  lift  locks  on  the  Central  Canal 619 

Description — Fontaine  cylindrical  sluice — Lock  gates — Time  of  lock- 
age— Cost. 

Chapter  X.  —Cable  towage  for  boats  on  canals  and  rivers 625 

Difficulties  of  cable  towage — Systems  adopted — Passage  around  bends 
— Method  of  attaching  the  boat  to  the  cable — The  grip — Length  of 
circuit — Cost. 


547 


548 


CONTENTS, 


Page. 


Chapter  XI.— Towage  by  a submerged  chain,  with  a fireless  engine.  631 
Chapter  XII. — System  for  supplying  the  canal  from  the  Marne  to 

the  Rhine  and  the  Eastern  Canai 635 

Chapter  XIII.— Oscillating  bridge  over  the  Dames  Canal  Lock 638 

Chapter  XIV. — Balanced  gates  at  the  place  where  the  Rhone  and 

Cette  Canal  crosses  the  Lez  River 638 

Chapter  XV.— Braye-en-Laonnois  Tunnel ". 642 

Geological  section  of  the  ground — Use  of  compressed  air — Accidents  by 
fire — Accessory  constructions. 

Chapter  XVI. — Navigation  of  the  Seine  from  Parls  to  the  sea....  649 

Chapter  XVII. — Embankment  works  for  the  improvement  of  the  tidal 

Seine 651 

Depth  of  water — Improvements — Alluvial  land — Results. 

Paper  by  Prof.  Vernon-Harcourt  on  the  principles  of  training 

RIVERS  THROUGH  TIDAL  ESTUARIES 653 

Introduction — Conflicting  opinions  respecting  methods — Investigation 
about  the  Seine  estuary— Prof.  Reynolds’s  working  model  of  the 
Mersey  estuary— Model  of  the  Seine  estuary — The  arrangements 
for  imitating  the  tidal  and  freshwater  flow — Trials  of  various  gran- 


ular substances  for  the  bed  of  the  estuary  in  the  model — Results 
of  working  with  Bagsliot  sand — Experiments  with  training  walls 
introduced  in  the  model — Principles  deduced  from  the  experiments. 

PART  II.— TIDAL.  COAST.  AND  HARBOR  WORKS. 

Chapter  XVIII.— Calais  Harbor  works 670 

History  — Sluicing  basin  — Docks  — Improvements  — Northwest  dike — 

Use  of  water  jets  in  driving  piles — Outer  harbor  quays — Foundation 
of  the  quays  by  the  system  of  water  jets — Dock  locks— Swing 
bridges — Hydraulic  machinery  for  operating  the  locks  and  bridges — 


Quays — Graving  dock — Barge  dock. 

Chapter  XIX.— The  new  outer  harbor  at  Boulogne 687 

State  of  Boulogne  Harbor  in  1878 — Project  for  a deep-water  harbor — 

Work  done  up  to  1889 — Description  of  the  dike — Results  obtained — 

Further  improvements. 

Chapter  XX. — Port  of  Havre— The  Bellot  Lock 694 

Iron  swing  bridges — Lock  gates — Hydraulic  apparatus — New  iron  dock 
sheds — Cost. 

Chapter  XXL — Port  of  Havre — Iron  wave-breaker  on  the  break- 
water on  THE  SOUTH  SIDE  OF  THE  OUTER  HARBOR 700 

Chapter  XXII. — Canal  from  Havre  to  Tancarville — Single  gate  of 

the  Tancarville  Lock 702 

Chapter  XXIII. — Slipway  built  by  the  chamber  of  commerce  at  Rouen 

FOR  THE  REPAIR  OF  SHIPS 704 

Chapter  XXIV.— Port  of  Honfleur 708 

Sluicing  Basin — Method  of  closing  the  sluicing  lock — Lock  gates — 

Weir  for  feeding  the  storage  basin — Description  of  the  weir  gates. 
Chapter  XXV. — Port  of  Honfleur — Siphons  between  the  storage 

BASIN  AND  THE  FOURTH  DOCK — AUTOMATIC  SIPHONAGE 715 

Chapter  XXVI. — Traversing  bridge  on  the  dock  locks  at  the  port 

of  St.  Malo-St.  Servan 718 

Position  and  general  arrangements— The  lifting  press — The  recuper- 
ator— Operation — Weight  and  cost. 


CONTENTS.  549 

Page. 

Chapter  XXVII.— Hydraulic  works  and  pneumatic  foundations  at 

Genoa 722 

Dry  docks  and  accessory  works — The  Quai  des  Graces — Character  of  the 
foundation — New  method  adopted  for  the  foundation — Caissons 
for  blasting  out  the  rocks — Boring  apparatus — Movable  caissons 
for  the  construction  of  the  quay  walls — Description  of  the  lock  for 
admitting  and  removing  material — The  great  floating  caisson  and 
its  mode  of  working— Supply  of  compressed  air,  etc. — Iron  centers 
for  the  arches  of  the  Quai  des  Graces. 

Chapter  XXVIII. — Port  of  Rochelle— Foundation  of  the  jetties  at 

La  Pallice 736 

Process  adopted  for  the  construction  of  the  blocks — Description  of  the 
caissons  and  air  locks.  Work  in  the  caisson — Displacement  of 
the  caisson — Access  to  the  caisson — Removal  of  the  submarine 
rocks — Cost. 

PART  III.— BRIDGES  AND  VIADUCTS. 


Chapter  XXIX.— The  new  steel  bridge  at  Rouen  on  the  Seine 745 

Chapter  XXX.— Reconstruction  of  the  roadway  on  the  suspension 

bridge  at  Tonnay-Charente— Alternately  twisted  cables..  748 

Chapter  XXXI.— The  lifting  bridge  at  La  Villette,  Paris 752 

Chapter  XXXII.— The  Garabit  Viaduct 756 

History — Description — The  horizontal  girders — The  roadway — The 


arch — The  iron  piers— Principal  dimensions — The  stresses — Erec- 
tion of  the  iron  work — Methods  of  raising  the  pieces — General 
information — Cost. 


Chapter  XXXIII. — Gour-noir  Viaduct 767 

Chapter  XXXIV.— Viaduct  over  the  river  Tardes ' 769 

Chapter  XXXV.— Consolidation  of  the  side  slopes  at  LaPlante 771 

Chapter  XXXVI.— Tunnel  through  Cabres  Pass  on  the  railroad 

from  Crest  to  Aspres-les-Veynes 773 

Chapter  XXXVII. — Cubzac  bridge  over  the  Dordogne 775 

The  viaduct— The  bridge  proper — Method  of  launching  by  steam — De- 
tails of  the  machinery  employed. 

Chapter  XXXVIII. — The  Crueize  Viaduct 781 

Chapter  XXXIX.— Construction  of  the  Castelet,  the  Laveur,  and 

the  Antoinette  bridges 782 

Description — Centers — Construction  of  the  arch. 

Chapter  XL. — The  Ceret  Bridge  789 

Chapter  XLI. — The  Crossing  of  the  Garronnf.  at  Marmande — The 

USE  OF  MASONRY  CAISSONS 792 

Chapter  XLII. — Oloron  Bridge  upon  the  Gave  d'Oloron  Railroad 

from  Pau  to  Oloron 796 

Chapter  XLIII.— The  Gravona  Bridge 798 

PART  IV.— CIVIL  CONSTRUCTION  AND  ARCHITECTURE. 

Chapter  XLIV.— Specimens  of  iron  construction  in  Paris 801 

Introduction — Borings  — Zschokke’s  bell  caisson  — Foundations — Iron 
work — Strength  of  the  iron  pillars  and  beams. 

Chapter  XLV. — The  Eiffel  Tower 806 

Introduction — Description  of  the  proposed  tower — Strength  and  sta- 
bility of  the  tower— Force  of  the  wind— Different  hypotheses 


550 


CONTENTS. 


Page. 

Chapter  XLV.— The  Eiffel  Tower— Continued. 

adopted  — Overturning  moment  —Anchorage  —Deflection  —Resis- 
tance of  the  tower  against  the  wind— Calculation  of  the  dimen- 
sions of  the  uprights— Construction— Situation — Borings — Use  of 
compressed  air— Foundations— Description  of  the  iron  work— De- 
tails of  the  foundation— Lightning  conductors — Erecting  scaffold- 
ings— Erecting  cranes — Method  of  raising  the  cranes — Erection  of 
the  first  and  second  stories — Erecting  cranes  above  the  second 
story — Method  of  shifting  the  crane — Protection  of  the  workmen — 
Arrangement  of  the  second  and  third  stories — Staircases  and  eleva- 
tors— Time  of  ascent — Verification  of  the  verticality  of  the  tower — 

Uses  of  the  tower — Strategical  operations — Names  of  eminent  men 
of  science  upon  the  tower — Statistics — Cost — Montyon  prize  in  me- 
chanics awarded  to  M.  Eiffel — Acknowledgments— Opposition  en- 
countered by  M.  Eiffel  in  the  erection  of  the  tower. 

Chapter  XLVI. — The  Machinery  Hall 832 

Introduction — The  Osiris  prize — Popular  estimate  of  the  machinery 
hall — Extracts  from  specifications — Foundations — Description  of 
the  principal  truss  girders  or  arched  ribs — Purlins  and  rafters — 

Erection — Method  adopted  by  Fives-Lille  & Co. — Method  of  raising 
the  purlins  and  rafters — Weight — Method  of  erection  adopted  by 
Cail  & Co. — The  great  vestibule — The  erecting  scaffoldings — The 
lateral  galleries — Construction  of  the  gables — Weight — Cost — 
Acknowledgments. 

PART  V.— LIGHT-HOUSES. 


Chapter  XLVII.—  Planier  Light-house 864 

Chapter  XLVIIL— Iron  light-house  at  Port  Vendres 867 

Chapter  XLIX. — Apparatus  2.66  meters  in  interior  diameter  called 

hyper-radiant,  for  lighting  Cape  Antifer 870 

Chapter  L. — Improvements  in  the  apparatus  in  light-houses  using 

mineral  oil 872 

Optical  apparatus — Spherical  reflector — Clockwork — Automatic  brake 
and  regulator — Electrical  indicator  of  the  stops  of  the  machine — 
Constant  level  lamps. 

Chapter  LI. — Improvements  recently  made  in  electric  light-houses.  876 


Bifocal  apparatus  — Motors  and  connections  — Magneto-electric  ma- 
chines— Working  of  the  machinery — Results — Electric  regulators 
and  indicators — Cost. 

Chapter  LII. — Acoustic  signals  in  connection  with  electric  light- 


houses  881 

Chapter  LIII.— The  illumination  of  isolated  buoys  and  beacons  by 

MEANS  OF  GASOLINE 882 

The  apparatus — Burners — Properties  of  petroleum  products — Arrange- 
ment of  the  reservoirs — Success — Cost. 

Chapter  LIV.— Graphic  method  of  quadrature 885 

By  M.  Ed.  Collignon,  Chief  Engineer  of  Roads  and  Bridges. 


CIVIL  ENGINEERING,  PUBLIC  WORKS,  AND  ARCHI- 
TECTURE. 


By  WILLIAM  WATSON,  Ph,  D. 


INTRODUCTION. 

The  information  contained  in  this  report  is  derived  from  official 
sources.  Most  of  that  relating  to  the  public  works  of  France  has 
been  obtained  from  the  notices  and  documents  collected  by  direction 
of  the  minister  of  public  works,  and  exhibited  in  a special  pavilion 
erected  for  the  purpose. 

For  a lai'ge  number  of  stereotyped  illustrations  of  these  works  I 
am  indebted  to  the  administration  of  roads  and  bridges,  through  the 
courtesy  of  M.  Collignon,  inspector  of  the  school  of  roads  and 
bridges.  I wish  also  to  express  my  obligations  to  M.  Schwebeld, 
the  accomplished  librarian  of  the  school,  and  to  M.  Boulard,  the 
superintendent  of  the  pavilion  of  public  works,  for  explanations 
and  valuable  suggestions. 

For  the  information  and  drawings  relating  to  the  port  of  Genoa 
and  the  submarine  work  of  the  outer  harbor  of  La  Pallice,  I am  in- 
debted to  the  contractor,  M.  Terrier,  of  the  firm  of  Zschokke  & P. 
Terrier. 

To  Mr.  L.  F.  Vernon-Harcourt  for  his  paper  on  the  training  of 
rivers  through  tidal  estuaries. 

To  MM.  Eiffel  and  Nougier  for  the  descriptions,  pamphlets,  pho- 
tographs, and  prints  relative  to  the  Eiffel  tower  and  the  Garabit  via- 
duct. 

To  M.  Contemin  and  his  assistant,  M.  Groclaude,  for  information, 
and  drawings  relative  to  machinery  hall. 

To  M.  Baudet  for  much  information  concerning  the  civil  construc- 
tions described,  including  portions  of  the  machinery  hall,  which 
were  erected  by  him,  as  well  as  the  lock  gates  and  dock  sheds  at 
Havre. 

A model  of  one  important  work,  viz,  the  Forth  bridge,  was  shown 
at  the  exhibition;  this  bridge  has  since  been  successfully  completed 
and  may  justly  be  considered  the  greatest  triumph  of  engineering 
skill.  An  elaborately  illustrated  account  of  this  structure  has  been 
published  in  Engineering,  and  it  has  not  been  thought  best,  for  this 
reason,  to  enter  upon  its  description  here,  as  the  author  had  no  infor- 
mation concerning  it  that  was  not  accessible  to  the  public. 


551 


PART  I -HYDRAULIC  ENGINEERING-RIVERS.  AND  CANALS. 


Chapter  I. 

HYDRAULIC  CANAL  LIFTS  AT  LES  FONTINETTES,  FRANCE,  AND  AT 
LA  LOUVIERE,  BELGIUM. 

TheNeufossd  Canal  unites  the  Aire  Canal  with  the  rivers  Lys  and 
Aa.  It  connects  Dunkirk,  Gravelines,  and  Calais  with  the  system  of 
internal  navigation,  and  has  an  annual  traffic  represented  by  13,000 
boats. 

The  Fontinettes  locks,  situated  on  this  canal  at  Arques,  near  St. 
Oiner,  consist  of  a chain  of  five  successive  locks  surmounting  a dif- 
ference of  level  of  13.13  meters. 

The  time  consumed  in  passing  through  these  locks  often  ex- 
ceeded two  hours;  the  system  of  crossing  was  consequently  aban- 
doned, and  one  day  the  locks  were  used  for  ascending  boats  and  the 
next  for  those  descending.  Much  time  was  thus  lost,  involving  con- 
stant crowding,  and  it  was  easy  to  see  that  the  capacity  of  the  locks 
would  soon  be  reached.  Again,  as  the  Fontinettes  locks  did  not  ad- 
mit boats  of  more  than  34.80  meters  in  length,  they  could  not  accom- 
modate those  of  38.50  meters,  carrying  loads  of  300  tons,  which  were 
in  use  on  the  northern  canals. 

(2)  To  remedy  this  deplorable  situation  the  Government  ordered 
the  construction  of  an  hydraulic  lift  by  the  side  of  the  Fontinettes 
locks,  and  similar  to  that  in  use  at  Anderton  in  England,  on  the 
Trent  and  Mersey  Canal,  which  accommodates  small  boats  of  from 
80  to  100  tons. 

The  Government  wished  thus  not  only  to  improve  the  passage  at 
Fontinettes,  but  also  to  try  the  experiment  of  raising  boats  of  300 
tons  burden  by  an  hydraulic  lift. 

(3)  Principle  of  the  lift. — The  lift,  properly  so  called,  consists  of 
two  iron  troughs  containing  the  water  in  which  the  boats  float. 
Eacii  trough  is  bolted  at  its  center  to  the  head  of  a piston,  or  ram, 
which  works  in  an  hydraulic  press  set  up  in  a basin.  The  two  presses 
communicate  by  a pipe  containing  a valve  serving  to  cut  off,  at  will, 
communication  between  the  cylinders. 

We  thus  have  an  hydraulic  balance,  and  it  is  sufficient  to  give  a 
certain  surcharge  of  water  to  one  of  the  troughs  when  the  valve  is 
opened,  in  order  that  one  trough  shall  descend,  and  in  doing  so  raise 
the  other.  Besides,  the  weight  of  the  trough  does  not  vary,  whether 
it  contains  a boat  or  not,  provided  the  water  in  it  stands  at  the  same 

level  in  both  cases. 

552 


Civil  Engineering,  etc.— PLATE  I. 


GENERAL  VIEW  OF  THE  HYDRAULIC  CANAL  LIFT  AT  LES  FONTINETTES. 


554 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


IT 


rWi 

" i 

Am 

Fig.  2.— Hydraulic  lift  at  Ties  Fontinertes.  Longitudinal  section  along  the  axis  of  the  trough.  A,  canal  bridge  ; B,  movable  trough  ; C,  pistons  ; D.  great 
presses  ; H,  frames  supporting  the  lifting  gates  ; I,  guides  ; K,  towers ; L,  lookout  cabin  : M,  machine  house  ; Q,  service  bridge  ; S,  capstan. 


Paris  Exposition  of  1889— Vol.  3.  Civil  Engineering,  etc.— PLATE  II 


HYDRAULIC  CANAL  LIFT  AT  LES  FONTINETTES.  VIEW  OF  THE  TROUGH  BASIN. 


CIVIL  ENGINEERING,  ETC. 


ooo 


(4)  Description  of  the  works. — A cut-off  was  made  in  the  right 
bank  of  the  Neu  fosse  Canal  parallel  to  the  Fontinettes  locks,  with  a 
depth  of  water  2.20  meters  and  a width  at  the  bottom  of  17.95  me- 
ters. It  is  provided  with  a guard  lock  6 meters  wide  at  the  junction 
of  the  excavation  and  embankment,  and  it  crosses  the  Boulogne  and 
St.  Omer  Railroad  by  an  iron  aqueduct  divided  into  two  independent 
lines,  A A,  each  with  a span  of  20.80  meters.  Immediately  below 
this  point  the  lift  is  placed.  (Fig.  1.) 

A general  view  of  the  lift  is  given  in  Plate  I. 

In  the  foreground  is  seen  the  iron  lattice  bridge  over  the  two 
branches  of  the  canal  containing  the  lift.  Immediately  behind  is 
the  lower  iron  frame  supporting  the  downstream  gates;  the  trough 
on  the  right  is  raised;  on  the  right  and  left  are  the  towers  with  their 
iron  guides  to  steady  the  trough  in  its  ascent  and  descent.  Behind 
the  first  tower,  on  the  left,  is  the  machine  house  containing  the 
accumulator,  the  turbines,  and  the  feed  pumps;  on  the  top  is  the 
lookout  cabin  containing  the  levers  for  opening  and  closing  all  the 
valves  used  in  operating  the  lift.  Still  farther  in  the  rear  are  the 
supports  for  the  upstream  gates,  also  containing  the  hydraulic  mov- 
ing apparatus.  Below,  in  the  rear,  is  the  iron  girder  bridge  carrying 
the  canal  over  the  Boulonge  and  St.  Omer  Railroad,  resting  on  the 
massive  abutment.  At  the  extreme  right  is  the  original  canal  lead- 
ing to  a flight  of  five  consecutive  locks. 

Plate  1 1 shows  the  trough  basin,  giving  a view  of  the  trough  as  seen 
from  beneath  when  it  is  raised,  and  of  the  parts  of  the  structure 
which  are  then  below  the  trough.  It  exhibits  the  junction  of  the 
square  head  of  the  ram  with  the  trough  bottom  and  the  details  of 
the  construction  of  the  latter.  On  the  side  of  the  house  is  seen  the 
guide;  beyond  is  the  gate  with  its  lifting  chain  and  guide  pulley, 
surmounted  by  the  iron  lattice  supports.  On  the  left  side  is  a little 
centrifugal  pump  for  draining  the  trough  basin. 

(5)  The  troughs. — Each  movable  trough,  B,  is  40.55  meters  long 
and  has  a working  length  of  39.50  meters.  It  is  formed  of  two  girders 
5. GO  meters  apart,  5.50  meters  in  depth  in  the  middle,  and  3.50  me- 
ters at  the  extremities,  not  including  the  angle  irons.  These  girders, 
carrying  the  corbels  supporting  the  footbridge,  are  united  by  cross 
girders  0.525  meters  high  and  1.50  meters  apart. 

The  four  middle  transverse  girders  are  1.50  meters  high;  to  these 
the  piston  head,  hollo'vved  out  for  this  purpose,  is  attached  by  strong 
brackets,  thus  forming  a rectangle  3.50  by  3.10  meters  with  a border 
0.010  meters  thick. 

The  minimum  depth  of  the  water  in  the  troughs  is  2. 10  meters; 
the  ends  are  closed  by  lifting  gates.  The  troughs  are  lodged  at  the 
bottom  in  a dry  masonry  basin  below  the  level  of  the  lower  bay, 
which  is  divided  into  two  compartments  by  a wall  5.20  meters  wide; 
each  compartment  has  its  lower  entrance  closed  by  a gate  at  the  ex- 
tremity of  each  aqueduct. 


556 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


(G)  The  pistons. — The  pistons  are  cast-iron  plungers  17.13  meters 
long,  2 meters  in  diameter,  and  0.07  meter  thick;  they  are  formed  in 
sections  2.80  meters  long  flanged  on  the  inside,  united  by  bolts  and 
made  water-tight  by  a ring  of  sheet  copper  inserted  between  each 
flange. 


If  i 

B 

1 

JJ 

Fig.  3.— Cross  section  through  the  transverse  axis  of  the  Hydraulic  lift  at  Les  Fontinettes.— Geo- 
logical section:  0 ravel  with  smooth  stones;  sand;  fossil  shells;  broken  tufa;  compact  tufa.— B B, 
movable  troughs;  C C,  pistons;  D D,  great  presses;  E E.  supply  pipes;  F,  connecting  valve;  1 1 1 1, 
guides  ; KKK.  towers  ; I.,  lookout  cabin;  PP,  compensating  reservoirs. 

(7)  The  presses. — The  great  presses  are  15.082  meters  high  and 
2.078  meters  in  diameter.  They  rest  upon  masses  of  cement  bdton 
at  the  bottom  of  the  pits,  which  are  4 meters  in  diameter  and  tubbed 


CIVIL  ENGINEERING,  ETC. 


557 


with  cast  iron.  The  presses  themselves  are  made  up  of  rolled  weld- 
less steel  hoops  0.155  meter  wide  and  0.00  meter  thick,  stepped  into 
each  other  at  half  thickness,  with  a joint  0.005  meter  high,  and  made 
water-tight  by  a copper  lining  0.003  meters  thick. 

Each  cylinder  is  stiffened  by  vertical  angle  irons,  fastened  to  a 
hexagonal  framing  below  the  press,  and  above  to  a collar  surround- 
ing the  cylinder.  Four  crossbeams  supporting  the  flooring,  and 
resting  upon  the  tubbing  of  the  pits,  complete  the  system.  The  bot- 
tom of  each  press  is  of  armor  plate  2.25  meters  square. 

The  joint  between  the  piston  and  the  press  is  formed  by  an  India- 
rubber  band,  lined  with  sheet  copper  and  lodged  in  an  annular  recess 
made  in  the  cylinder  cover;  this  lining  is  kept  in  place  by  a bayonet 
attachment.  , 

(8)  The  presses  communicate  by  an  iron  pipe  0.25  meters  in 
diameter  inside,  starting  from  the  bottom  of  eacli  cylinder  and 
ascending  the  corresponding  pit;  the  pipe  has  a horizontal  branch 
at  the  bottom  of  the  basin  between  the  two  pits  and  contains  a valve 
in  the  middle.  This  branch  has  also  tubes  connecting  with  two  dis- 
tributors, by  means  of  which  water  may  be  forced  under  pressure 
into  either  press,  or  allowed  to  escape  therefrom. 

(9)  Guides. — The  troughs  are  guided  on  the  upstream  end  and  in 
the  middle.  The  upstream  guides  are  fixed  to  the  downstream  pier 
of  the  aqueduct,  which  forms  the  lift  wall.  The  center  guides,  D D, 
which  are  the  most  important,  rest  against  three  massive  square 
towers.  They  consist  of  strong  steel  shoes  attached  to  the  troughs 
and  clasping  the  cast-iron  guide  bars.  The  downstream  ends  are 
not  guided. 

(10)  The  engineer  in  the  valve-house,  L,  at  the  top  of  the  central 
tower  directs  the  whole  apparatus,  opens  and  closes  the  connecting 
valve  between  the  presses,  and  the  valves  of  the  distributors.  Access 
to  this  house  is  afforded  by  the  tower  staircase  or  by  a footbridge 
from  the  top  of  the  lift  wall. 

(11)  The  side  towers  contain  wrought-iron  cylindrical  reservoirs 
2 meters  in  diameter — equal  to  the  exterior  diameter  of  the  pistons. 
Each  of  these  compensating  reservoirs,  as  they  are  called,  can  be  put 
into  communication  with  the  corresponding  trough  by  a jointed  pipe. 

(12)  When  one  trough  is  raised  to  the  end  of  its  course  there  is  a 
play  of  about  0.045  meter  between  its  upstream  extremity  and 
the  downstream  end  of  the  aqueduct  connecting  with  it.  At  the 
moment  of  raising  the  gates  to  allow  a boat  to  enter  or  to  pass  out 
of  a trough  the  joint  is  made,  by  an  India-rubber  hose  running 
round  the  end  of  the  aqueduct  and  protected  by  springs.  This  hose 
is  inflated  with  air  at  a pressure  of  l£  atmospheres.  Little  valves 
inserted  in  the  gates  permit  this  space  (between  the  gates)  to  be  filled 
with  water  before  making  the  connection.  The  same  arrangement 
is  made  for  the  lower  bay  joint. 


558 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


(13)  Porticos  constructed  on  the  lift  wall,  and  also  on  the  tail  wall, 
have,  on  their  tops,  hydraulic  apparatus  for  lifting  the  gates.  The 
gates,  which  are  balanced  to  a great  extent  by  counterweights, 
allow,  when  raised,  a free  height  of  3.70  meters  above  the  level  of 
the  water.  Below  the  lift,  a footbridge,  Q,  connects  the  two  banks 
with  the  central  masonry  wall. 

(14)  The  machinery  (PI.  Ill)  placed  in  a building,  M,  between  the 
two  compartments  of  the  dry  basin  on  the  upstream  side  of  the  cen- 
tral tower,  consists  of  two  turbines  driven  by  the  water  of  the  upper 
bay,  brought  into  a tank  between  the  two  lines  of  the  aqueduct. 
One  turbine  of  50  horse  power  drives  four  double-acting  force  pumps 
coupled  together  two  and  two,  and  supplying  an  accumulator  of 
1,200  liters  capacity.  The  other  15  horse-power  turbine  drives  the 
air  compressor  for  the  inflation  of  the  joining  hose,  and  also  a cen- 
trifugal pump  which  serves  to  keep  the  trough  basins  clear  of  water, 
whether  from  leakage  or  false  maneuvering. 

A little  steam  engine  works  the  pump  when  the  upper  bay  is  not 
in  use. 

(15)  The  weight  to  be  raised,  including  a piston,  a trough,  the 
water,  and  a boat  floating  in  it,  amounts  to  about  800  tons;  the 
pressure  in  the  presses  is,  therefore,  about  25  atmospheres.  But  the 
accumulator  has  been  loaded  to  30  atmospheres  to  make  sure  of  the 
efficient  working  of  the  presses  for  lifting  the  gates. 

The  compensating  reservoirs  were  intended  by  the  authors  of  the 
project  to  reduce  the  consumption  of  water,  but  it  has  not  been 
thought  best  to  use  them. 

(10)  Method  of  ivorking  the  lift. — The  lift  is  worked  as  follows: 
One  of  the  troughs  being  raised  to  the  height  of  its  course  and  con- 
taining a depth  of  water  2.40  meters,  the  joint  is  made  by  opening 
the  cock  admitting  compressed  air  into  the  hose  running  around 
the  face  of  the  end  of  the  aqueduct.  Then  the  trough  and  aqueduct 
bridge  are  hooked  together,  and  at  the  same  time  the  space  between 
the  gates  is  filled  by  means  of  a little  valve.  The  two  gates  are  then 
raised  together  by  means  of  a counterpoise  and  the  hydraulic  appa- 
ratus; a boat  is  hauled  into  the  trough,  then  the  gates  are  lowered 
and  unhooked,  the  valve  is  closed,  and  the  air  in  the  rubber  hose 
allowed  to  escape. 

During  this  time  similar  operations  have  taken  place  below;  the 
other  trough  being  at  the  end  of  its  course,  resting  on  wooden  blocks 
and  containing  water  2.10  meters  deep.  The  upper  trough  has  thus 
a surcharge  of  0.30  of  a meter  in  depth,  corresponding  to  about  64.6 
tons. 

The  connecting  valve  between  the  presses  is  then  opened  and  one 
trough  descends  while  the  other  rises.  The  motion  is  stopped  by 
closing  the  connecting  valve  when  the  level  in  the  ascending  trough 
is  0.30  of  a meter  below  that  of  the  upper  bay.  The  descending 


Paris  Exposition  of  1889 — Vol.  3.  Civil  Engineering,  etc.  PLATE  III. 


HYDRAULIC  CANAL  LIFT  AT  LES  FONTINETTES.  VIEW  OF  THE  PUMPING  MACHINERY. 


CIVIL  ENGINEERING,  ETC. 


559 


trough  has  also  its  level  0.30  of  a meter  above  the  level  of  the 
lower  bay.  The  joints  are  formed,  and  the  gates  lifted,  slightly  at 
first,  then  completely.  The  upper  trough  takes  its  surcharge  for  the 
following  operation  while  the  lower  one  gives  up  its  water  ballast  to 
the  lower  bay.  The  boats  can  then  be  hauled  out  and  replaced  by 
others. 

The  position  of  a trough  may  be  corrected  either  before  or  after 
the  opening  of  the  lifting  gates.  It  is  sufficient  for  this  purpose  to 
move  the  distributor  valves  so  as  to  allow  water  to  escape  from  the 
press  or  to  introduce  water  under  pressure  from  the  accumulator 

into  it.  ' 

Also  safety  valves  are  introduced,  opening  automatically,  and  thus 
preventing  the  trough  from  rising  too  high,  which  might  be  dan- 
gerous. 

(17)  At  the  beginning  of  the  operation,  the  press  of  the  upper 
trough  contains  41  tons  of  water  more  than  that  of  the  lower.  The 
force  producing  the  descent  attains  about  10G  tons.  This  force  pro- 
gressively diminishes,  since  the  water  in  the  first  press  passes  gradu- 
ally into  the  second,  and  at  the  end  of  the  operation  the  force  is  only 
24  tons;  this  is  necessary  to  overcome  the  friction  and  passive  resist- 
ances. This  force  tvould  be  in  reality  only  12  tons  if  the  connecting 
pipe  was  entirely  free,  but  it  was  thought  best  to  reduce  the  section 
by  valves  and  thus  regulate  the  apparatus,  in  order  to  avoid  either 
an  excessive  velocity  or  a premature  stoppage  in  case  of  error  in 
taking  the  surcharge. 

As  we  see,  the  initial  force  diminishes  and  the  motion  slackens 
continuously,  so  that  each  trough  comes  to  the  end  of  its  course  with 
nearly  no  velocity. 

(18)  The  actual  time  of  the  up  and  down  movement  of  a troxigli  is 
on  an  average  2G  minutes,  made  up  as  follows: 

Minutes. 


Entrance  of  the  boat  and  closing  of  the  gates  * 8 

Ascent  and  descent  of  the  troughs  f 5 

Correction  of  the  position  of  the  troughs 3 

Opening  the  gates  and  hauling  out  the  boats 10 

Total “ 26 


When  the  hydraulic  capstans  are  set  up  to  hasten  the  entrance 
and  exit  of  boats,  which  is  now  done  by  men,  this  time  will  be 
reduced  to  20  minutes,  and  six  boats  per  hour  will  be  passed. 

The  works  were  begun  at  the  end  of  1883.  The  first  attempts  to 
work  the  lift  took  place  in  November,  1887,  and  it  was  opened  for 
traffic  the  20th  of  April,  18^8. 

*This  is  a mean  of  4,769  operations. 

t This  time  would  have  been  reduced  to  3 minutes  if  the  section  of  the  conduit 
between  the  presses  had  not  been  reduced  as  a precautionary  measure. 


560 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


(19)  The  towers. — The  slightest  movement  of  the  towers  would 
affect  the  vertically  of  the  guides ; they  were  accordingly  built  on 
piles. 

(20)  Erection  of  the  presses. — Ingenious  devices  were  adopted  to 
set  up  the  presses  and  pistons. 

The  troughs  were  put  together  upon  scaffoldings  7 meters  above 
bottom  of  the  basin,  leaving  the  central  portion  above  the  pits  open. 
In  this  position  the  girders  of  the  troughs  served  to  support  a trav- 
eling crane  which  carried  the  pieces  to  be  lowered  into  the  pits. 

Each  press  was  erected  as  follows : The  hexagonal  framing  hav- 
ing been  placed,  the  bottom  of  the  press  with  the  first  steel  rings 
and  the  lower  elbow  of  the  connecting  pipe  were  lowered,  the  whole 
having  been  lined  with  copper,  the  latter  projecting  beyond  the 
rings.  A copper  collar  2.44  meters  high,  made  in  the  workshop,  was 
then  riveted  and  soldered  to  the  lining  already  placed  so  as  to  form 
on  the  exterior  a regular  cylindrical  surface.  The  collar  had  a di- 
ameter very  slightly  less  than  the  interior  diameter  of  the  rings. 
The  latter  were  threaded  on  to  the  collar  to  a certain  height,  and 
then  a new  collar  was  placed,  and  so  on. 

The  presses  being  set  up,  they  were  tested  by  a hand  pump  up  to 
54  atmospheres. 

The  presses  were  found  perfectly  tight,  and  the  result  of  the  test 
was  to  press  the  copper  lining  exactly  against  the  steel  rings. 

(21)  The  pistons. — After  this  trial  the  pistons  were  set  up  as  fol- 
lows: Each  press  was  filled  with  water  and  the  connecting  pipe 
closed  by  a plug  having  in  it  a three-way  cock.  The  first  section  of 
the  piston  was  placed  so  as  to  be  supported  by  the  water  and  project 
out  of  the  press.  The  second  section  was  then  placed  and  the  joint 
carefully  made.  By  allowing  a small  quantity  of  water  to  escape 
from  the  cylinder  the  two  sections  were  lowered  so  as  to  put  on  the 
third,  and  so  on.  If  one  of  the  joints  was  not  tight  it  was  discov- 
ered immediately  by  means  of  the  hand  pump,  the  piston  was  raised, 
and  the  defect  corrected. 

When  the  piston  was  in  place  the  central  portion  of  the  trough 
was  completed.  Then  the  piston  head  was  raised  so  as  to  bolt  it  on 
to  the  cross  girders.  The  whole  was  then  raised  slowly  by  the  hand 
pump  and  the  trough  lifted  from  its  scaffolding,  which  was  then 
removed. 

(22)  Cost. — The  cost  was  nearly  as  follows: 


Francs. 

Lands  and  buildings  bought 165, 017. 32 

Foundation  (by  compressed  air)  of  the  lift  wall 97,000.00 

Earthwork  and  masonry 583,492.71 

Ironwork,  including  the  sinking  of  the  pits 831,102. 00 

Salary  and  patent  royalty  to  Mr.  Edwin  Clark 47, 670. 00 

Sundries 145,717.97 


Total..., 1,870,000.00 


CIVIL  ENGINEERING,  ETC. 


561 


The  location  of  the  Fontinettes  lift  was  necessarily  fixed;  conse- 
quently the  purchase  of  lands  and  buildings  of  great  value,  the  ex- 
pense of  making  a cut-off  in  a high  filling,  of  crossing  a railroad 
track,  and  of  laying  foundations  under  great  difficulties,  could  not 
have  been  avoided;  besides,  the  Government  made  its  contract  with 
Cail  & Co.  when  the  price  of  iron  was  very  high.  Considering  the 
circumstances,  it  may  be  affirmed  that  if  a similar  lift  were  to  be 
constructed  on  a new  canal,  the  total  expense  would  not  exceed 
1,300,000  or  1,400,000  francs. 

(23)  The  plans  for  the  earthwork  and  masonry  were  prepared  by 
Messrs.  Gruson,  chief  engineer,  and  Cetre,  assistant  engineer,  who 
directed  the  works. 

The  contract  for  the  metallic  portion  was  awarded  to  Cail  & Co., 
who  intrusted  it  to  M.  Barbet,  their  chief  engineer.  Most  of  the 
work  of  erection  was  directed  by  M.  Ballon. 

SUMMARY. 

Les  Fontinettes  lift — Neufosse  Canal , France. 


Trough — 

Length meters..  39.50 

Breadth do ... . 5. 60 

Depth  of  water do 2. 10 

Press — copper  internal  cylinder  with  exterior  weldless  steel  hoops. 

Thickness  of  copper  cylinder meters. . 0. 003 

Thickness  exterior  steel  hoops do  . . . 0. 060 

Length  of  press do. ...  15. 682 

Length  of  stroke  (height  of  lift) do. ...  13. 13 

Pressure  in  the  press atmospheres. . 25 

Ram  or  piston — 

Thickness  of  cast  iron meters. . 0.070 

External  diameter do....  2.00 

Total  weight  lifted,  including  water,  trough,  and  ram,  800  tons. 

Equivalent  to  a pressure  of  25  atmospheres. 

The  contents  of  one  stroke,  in  water tons. . 41 

Equivalent  to  a surcharge  on  the  trough  of meter. . 0. 20 

Actual  surcharge  used tons. . 64. 6 

Equivalent  to  a depth  of  water  of meter. . 0. 30 

Size  of  boats  lifted tons. . 300 

Actual  time  of  lift minutes. . 5 


Acknowledgment. — I wish  in  this  connection  to  express  my  indebt- 
edness to  M.  Gruson,  chief  engineer  of  roads  and  bridges,  for  the  in- 
formation concerning  this  interesting  subject  as  well  as  for  the  three 
figures  which  accompany  it. 

THE  LIFT  AT  LA  LOUVIERE. 

(24)  This  lift  is  situated  in  Belgium  at  La  Louvifere  station  on  the 
railroad  between  Mons  and  Namur,  on  what  is  called  the  Center 
Canal,  which,  when  finished,  will  unite  the  Mons  and  Conde  Canal 
H.  Ex.  410 — vol  hi 3G 


562 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


with  a branch  ( i . e.,  the  Houdeng-Goegnies)  of  that  from  Charleroi 
to  Brussels.  The  canal  itself  is  only  15  kilometers  long,  but  the  chief 
difficulty  is  in  a section  of  it  7 kilometers  long,  from  La  Louvi^re  to 
Thieu,  with  a fall  of  66.19G  meters,  which  it  is  proposed  to  surmount 
by  the  construction  of  four  lifts. 

(25)  The  first  lift  already  completed  is  in  the  commune  Houdeng- 
Goegnies,  not  far  from  La  Louviere,  so  that  it  is  sometimes  called 
the  Houdeng  lift. 

The  masonry  work  of  this  lift  was  begun  on  the  15th  of  May,  1885, 
and  the  ironwork  was  finished  in  the  beginning  of  1888. 

It  is  not  proposed  to  consider  here  the  motives  which  induced  the 
Belgian  Government  to  adopt  the  lift  system,  nor  to  repeat  a detailed 
description  of  it.  The  two  lifts  of  Fontinettes  and  La  Louvikre  are 
similar  in  all  their  essential  parts;  they  only  differ  in  their  dimen- 
sions, their  weight,  and  in  some  details  of  construction,  which  we 
now  propose  to  notice. 

(2G)  The  presses. — The  only  real  difficulties  met  with  were  in  the 
construction  of  the  presses  for  raising  the  troughs.  These  are  the 
most  important  and  dangerous  parts  of  the  system.  Upon  them  the 
stability  and  equilibrium  depend ; they  must  have  unusual  dimen- 
sions; it  takes  a certain  amount  of  audacity  to  put  a load  of  2,096,000 
kilogrammes  upon  two  presses,  requiring  their  interior  diameters  to 
be  2.06  meters  each,  with  a permanent  tension  of  34  atmospheres. 

(27)  We  have  already  seen  how  the  problem  was  solved  in  France. 
In  Belgium,  after  many  experiments,  it  was  decided  to  form  the 
presses  in  cylindrical  cast-iron  sections  0.10  meter  thick,  2.0G  meters 
in  diameter,  and  2 meters  high,  around  which  weldless  steel  coils  0.05 
meter  thick  and  0.152  high  are  shrunk  on  so  tightly  as  to  prevent 
the  cast  iron  from  having,  at  the  interior  concave  surface,  a stress  of 
more  than  1 kilogram  per  square  millimeter  with  a tension  of  34 
atmospheres  inside  the  press. 

(28)  Tests  of  the  iron  and  steel. — One  of  the  sections  broke  on 
trial  at  a pressure  of  146.5  atmospheres.  The  steel  has  a tensile 
strength  of  46.87  kilograms  per  square  millimeter  with  an  elongation 
of  25  per  cent  at  the  point  of  rupture. 

The  cast  iron,  run  into  little  bars,  had  a tensile  strength  of  17.53 
kilograms  and  a resistance  to  compression  of  73.49  kilogrammes. 
Finally,  and  this  is  the  most  important  test,  a cast-iron  section 
hooped  with  steel,  after  a series  of  trials  going  up  to  200  atmospheres, 
broke  at  265  atmospheres,  the  cast  iron  only  having  given  way  with- 
out producing  a rupture  or  any  alteration  in  the  steel  hoops. 

We  may  therefore  consider  the  resistance  of  the  presses  at  least 
eight  times  superior  to  the  permanent  tension  to  which  they  are 
exposed. 

The  cast  iron  here  plays  the  part  of  a tight  lining  only,  and  it 
seems  more  simple  and  rational,  at  least  in  theory,  to  replace  it  with 


CIVIL  ENGINEERING,  ETC.  563 

copper  a few  millimeters  thick,  and  depend  wholly  on  the  steel 
hoops  for  strength,  as  in  the  French  lift. 

(29)  The  pistons — Each  cast-iron  piston  has  three  parts ; the  head, 
which  supports  the  trough,  and  is  3.20  meters  square,  and  1.40  meters 
high ; the  shaft,  composed  of  8 sections,  each  2.13  meters  high  and 
0.075  meter  thick,  bolted  together;  and  the  foot,  which  is  a spherical 
segment  1 meter  in  height. 

(30)  The  communication  between  the  presses  takes  place  near  the 
top  through  a flanged  annulus  bolted  in  between  two  segments,  thus 
forming  practically  the  strongest  portion  of  the  press,  which  is  fed 
through  a series  of  holes  0.05  meter  in  diameter  made  in  the  annu- 
lus ; the  two  distributing  annuli  are  connected  by  a special  pipe. 

It  will  be  remembered  that  in  the  Fontinette  lift  the  presses  are 
connected  at  the  bottom,  thus  requiring  a pipe  double  the  height  of 
the  pits. 

The  spaces  between  the  troughs  and  the  aqueducts,  above  and 
below,  are  closed  by  metallic  wedges  lined  with  India  rubber.  Sets 
of  hydraulic  apparatus  driven  by  an  accumulator  containing  water 
under  a pressure  of  40  atmospheres  drive  these  wedges,  lift  the  gates 
of  the  aqueducts  and  troughs,  and  turn  the  capstans  for  hauling  the 
boats  in  and  out  of  the  lift. 

Cost. — The  cost  of  construction  of  La  Louvi&re  lift  is  as  follows: 


Francs. 

Purchase  of  lands 11,273.00 

Earthwork  and  masonry,  including  the  tubbed  pits  and  machinery 

houses 402,163.36 

House  for  the  engineers 26,891 . 68 

Metallic  portion,  including  the  machinery 899,062:71 

Patent  rights,  and  salaries  of  L.  Clark  Stanfield,  and  E.  Clark 65,586.61 


Total 1,404,979.36 


If  we  add  the  cost  of  journeys,  plans,  committees  of  consultation, 
and  oversight,  the  sum  will  amount  to  at  least  1,500,000  francs. 

(31)  Precautions  against  frost. — During  heavy  frosts  the  troughs 
are  both  lowered,  and  the  presses  and  pipes  emptied.  In  the  new 
lifts  about  to  be  erected  by  the  Belgian  Government  all  the  pipes 
will  be  protected  from  frost  by  being  inclosed  in  large  masonry 
chambers  in  which  fire  can  be  kept;  the  same  precautions  are  taken 
iu  reference  to  the  valves,  the  pumps,  and  the  hydraulic  machinery. 

(32)  Conclusion. — The  experience  acquired  and  the  observations 
made  in  the  construction  and  working  of  this  lift  have  suggested 
numerous  and  important  improvements  which  will  be  introduced 
into  the  lifts  now  in  process  of  construction.  The  whole  apparatus 
will  be  considerably  simplified.  The  compensating  reservoirs  have 
been  definitely  abandoned,  and  the  footbridges  around  the  troughs 
dispensed  with.* 


lie  port  of  M.  Duffourny. 


I 


564  UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


The  iron  aqueducts  uniting  the  upstream  end  of  the  canal  with  the 
troughs  are  replaced  by  masonry  ones.  The  wedges  are  fixed  with 
a possibility  of  adjusting  the  upper  one  by  hand.  The  downstream 
guide  is  omitted,  and  every  cause  of  accident  due  to  the  spontaneous 
action  of  water  under  pressure  is  carefully  removed  by  taking  care 
to  move  by  hand  the  wedges  and  the  hooking  bolts  of  the  gates. 
The  operating  levers  worked  by  hand  are  interlocking,  and  abso- 
lute security  results  from  the  fact  that  an  error  in  operating  is  me- 
chanically impossible. 

The  bottoms  of  the  basins  have  been  raised  considerably  by  giving 
a more  natural  form  to  the  longitudinal  trough  girders,  and  the 
weight  of  all  the  movable  parts  of  the  system  has  been  reduced  by 
the  substitution  of  steel  for  iron.  A last  improvement  is  the  protec- 
tion of  the  pipes  and  valves  from  the  action  of  the  frost. 


SUMMARY. 

La  Louviere  lift,  Canal  du  centre , Belgium. 


Trough : 

Length meters. . 

Breadth do. . . 

Depth  do... 

Weight tons. . 

Draft  of  water meters. . 

Ram  or  piston — cast  iron  : 

Diameter meters. . 

Thickness do. . . 

Length do. . . 

Weight tons. . 

Press — cast  iron,  hooped  with  continuous  steel  coils : 

Internal  diameter meters. . 

Thickness  of  cast-iron  core do. . . 

Thickness  of  steel  coils do. . . 

Length  of  press do . . . 

Length  of  stroke do. . . 

Weight  of  trough,  water,  and  piston tons. . 

Equivalent  to  a pressure  of atmospheres. . 

The  contents  of  one  stroke  in  water  weighs .tons. . 

Working  surcharge  0.25  meters do. . . 

Actual  time  of  lift,  from  2 to  3 minutes. 

Size  of  barges  lifted tons. . 


Total  time,  including  entering  and  departure  of  a barge  in  each 
direction,  15  minutes. 


43.000 

5.800 

3.250 

296 

2.400 

2.000 

0.075 

19.440 

80 

2.060 

0.100 

0.050 

19.590 

15.397 

1,048 

34 

49.3 

63 

400 


Chapter  II.— The  movable  dam  at  Suresnes  on  the  Seine. 

(34)  The  ueedle  dam  constructed  at  Suresnes  in  I860  assured  a 
draft  of  water  through  Paris  of  2.20  meters;  to  obtain  one  of  3.20 
meters  above  Paris  it  was  decided  in  1880  to  reconstruct  the  dam  so 
as  to  have  an  additional  fall  of  0. 97  meters. 


CIVIL  ENGINEERING,  ETC. 


565 


The  river  Seine  is  divided  at  Suresnes  into  three  branches  by  the 
Folies  and  Rothschild  islands.  The  dam  is  built  at  the  head  of 
these  islands  and  consists  of  three  separate  passes.  Looking  down 
the  stream  on  the  left  is  the  navigable  pass,  72.38  meters.  To  the 
right,  between  Rothschild  and  Folie  islands,  is  the  waste  weir  or 
intermediate  pass,  62.38  meters;  to  the  extreme  right  is  the  raised 
pass,  62.38  meters;  the  total  length,  197.14  meters. 


Above  and  below  each  pass  are  the  aprons  marked  R.  Next  to 
the  navigable  p'iss  are  the  little  lock,  P,  the  old  lock,  A,  and  the  great 
lock,  G.  On  the  left  bank  is  the  lockman’s  house,  E,  and  on  each  of 
the  two  islands  houses,  B B,  for  the  “ bar ri agists  ” or  dam  keepers. 

The  rectangle  in  front  of  the  navigable  pass  shows  the  location  of 
the  old  dam,  and  the  old  weir  extending  from  the  end  of  Rothschild 
Island  to  the  outer  end  of  the  rectangle. 


566 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


The  normal  fall  is  3.27  meters. 

(35)  The  dam  is  closed  by  a method  imitated  from  Poiree’s  sys- 
tem of  needle  dams;  Poirde's  frames  (fermettes),  Fig.  5,  have  been 
retained,  but  with  such  modifications  as  were  requisite  to  withstand 
the  increased  pressure  due  to  the  unprecedented  difference  of  level. 


Number  of 
frames. 

Height  of 
frames. 

Weight  of 
a frame. 

Cost. 

Meters. 

Kilos. 

Francs. 

Navigable  pass  

58 

6. 

1,800 

1,500 

Raised  pass 

50 

5. 49 

1,350 

1,135 

Waste  weir 

50 

4.14 

800 

660 

(35)  Frames. — Each  frame  (Fig.  5)  consists  of  a downstream  and 
upstream  upright,  united  by  horizontal  and  diagonal  bracing.  These 
uprights,  instead  of  being  merely  plates,  are  made  up  of  channel 
iron  put  together  so  as  to  form  (Fig.  6)  box  girders.  These  girders 
have  the  advantage  of  resisting  equally  well  in  the  direction  of  the 
water  pressure  and  in  that  at  right  angles,  produced  by  raising  or 
lowering  the  frames.  To  vary  the  resistance  in  the  first  direction  it 
is  only  necessary  to  increase  the  distance  between  the  channel  irons; 
to  vary  it  in  the  direction  at  right  angles  it  is  sufficient  to  increase 
the  number  of  irons. 

The  bracing  consists  only  of  channel  irons  having  nearly  the  same 
dimensions  as  those  of  the  uprights. 

The  frames,  1.25  meters  apart,  are  united  by  three  distinct  rails 
which  serve  to  carry  the  hoisting  windlass  and  the  planks  of  the 
service  bridge  crossing  all  three  passes. 

(30)  Operations. — The  difficulties  in  raising  or  lowering  the  frames 
are  satisfactorily  overcome  by  the  use  of  Megy’s  patent  windlass. 

All  the  frames  of  the  Seine  pass  are  united  by  a continuous  chain 
by  means  of  link  catches  placed  on  their  upper  cross  brace.  The 
length  of  the  chain  between  two  successive  frames  is  greater  than 
the  distance  between  the  axes  of  rotation,  so  that  six  frames  are 
lowered  or  raised  like  the  sticks  of  a fan  ; the  chain  is  hauled  in  by 
a windlass  placed  on  the  abutment  of  the  pass. 

By  this  system,  having  put  the  first  frame  in  place,  it  is  only  nec- 
essary to  haul  in  a short  length  of  chain  to  bring  the  second  into  its 
upright  position,  and  the  operations  of  opening  and  closing  the 
passes  are  almost  reduced  to  the  taking  up  or  putting  down  of  the 
rails  and  planks  of  the  service  bridge. 

At  Suresnes  the  opening  of  the  navigable  pass,  72.38  meters  in 
length,  is  accomplished  in  3 hours,  and  the  closing  in  5 hours;  al- 
though each  of  the  fifty-eight  frames  weighs  1,800  kilograms.  The 
following  table  indicates  the  diameter  of  the  chains  and  the  cost  of 
setting  up  of  three  dams. 


. 


CIVIL  ENGINEERING,  ETC, 


567 


MOVABLE  DAM  AT  SURESNES. 


3m,700  

Fio.  5.  — Movable  frame  (fermette)  of  the  navigable  pass. 


Fio.  6.  —Transverse  section  of  the  upstream 
upright. 


Fio.  7 —Transverse  section  of  the  downstream 
upright 


0 10 


568 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


Power  of 
windlass. 

Diameter  of 
the  chains. 

Total  cost. 

Navigable  pass 

Tons. 

10 

mm. 

26 

Francs. 

9,400 

Waste  weir 

4 

17.5 

5,400 

Raised  pass 

6 

21 

6,600 

(37)  The  flooi-ing,  fixed  in  the  masonry,  has  the  peculiarity  of  hav- 
ing no  portion  hollowed  out  to  receive  the  frame.  The  sill  is  placed 
at  such  a height  as  to  protect  the  frame  when  lowered,  but  at  a cer- 
tain distance  from  them  it  is  united  by  an  inclined  plane  to  the  row 


of  cut  stones  containing  the  upstream  axle  bearing.  These  stones 
project  a distance  of  0.30  meter,  and  beyond  them  the  flooring  is 
horizontal.  Hence  no  deposit  can  be  formed  to  obstruct  the  lower- 


CIVIL  ENGINEERING,  ETC. 


f>69 


ing  of  the  frames.  Iron  sockets  placed  on  each  side  of  the  frames 
allow  the  formation  of  a cofferdam  in  case  of  need,  with  the  aid  of 
a windlass,  for  the  purpose  of  making  repairs. 

(36)  Panels. — The  dam  is  closed  both  by  M.  Boult's  panels  and  by 
IVr.  Camera’s  curtains.  (The  latter  will  be  hereafter  fully  explained). 

M.  Boule’s  panels  are  of  wood,  1.22  meters  wide  by  1.10  meters 
high,  varying  from  0.04  to  0.09  meter  in  thickness. 

A panel  of  0.09  meter  is  placed  between  two  frames  of  the  navi- 
gable pass  at  the  bottom,  then  one  of  0.08  meter,  followed  by  one 
of  0.07,  0.06,  and  finally  one  of  0.04  meter.  (Fig.  8). 

The  water  flows  over  the  tops  of  the  panels,  and  the  opening  takes 
place  in  horizontal  layers;  the  upper  panels  across  the  dam  are  first 
removed,  then  the  second,  the  third,  and  so  on  to  the  last;  the  flow 
always  passing  over  the  top. 

This  apparatus  is  strong,  simple,  and  easily  operated,  for,  as  the 
panels  are  removed  the  head  falls,  and  consequently  the  pressure 
diminishes,  so  that  the  effort  to  raise  a panel  under  water  is  always 
slight,  and  about  the  same  whatever  height  the  dam  may  have. 

(37)  Handling  the  jmnels. — The  panels  are  handled  by  means  of 
of  a windlass  with  a long  straight  rack  terminated  by  a hook  and 
guided  by  the  frames  themselves. 

(38)  Cost. — The  works  for  the  erection  of  the  dam  were  begun  in 
1882,  and  finished  in  1885,  at  a total  cost  of  2,799,958  francs,  includ- 
ing those  for  the  protection  of  the  banks  in  the  three  passes,  the 
earthwork  on  the  islands,  the  storehouses  and  dwellings  for  the 
lockmen,  etc. 

The  dam,  properly  speaking,  including  the  abutments,  piers,  floor- 
ing, and  movable  parts  cost,  per  running  meter — 


Francs. 

For  the  navigable  pass  (frames  6.01  meters) 12,262 

For  the  raised  pass  (frames  5.49  meters) 10.817 

For  the  waste  weir  (frames  4.14  meters) 7,727 

Average  cost  for  the  dam  per  running  meter 10,370 


The  following  table  indicates  the  weight  and  prices  of  the  different 
panels : 


Thickness  of  panels. 

Weight. 

Cost. 

Meters. 

Kilos. 

Francs. 

0.04  

83 

41.01 

0.06 

115 

52.01 

0.07 

138 

58.95 

0.08  ...  

147 

80.40 

0.09 

ia? 

70.84 

Total  for  one  span 

664 

283.21 

The  project  was  prepared  and  the  works  executed  under  the  direc- 
tion of  M.  Bould,  chief  engineer,  and  MM.  Nicou  and  Luneau,  as- 
sistant engineers. 


570 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


Chapter  III.— Marly  dam  on  the  Seine. 

(39)  The  old  Marly  dam  which  consisted  of  five  piers  and  two 
abutments,  supporting  six  spans  of  planks  5 meters  long,  with  a 
cross  section  of  25  x 20  millimeters,  very  difficult  to  handle,  and 
indeed  often  impossible  in  times  of  freshet,  has  just  been  replaced  by 
a Poiree  dam.  that  is,  the  piers  have  been  replaced  by  iron  frames  like 
those  of  the  movable  dams;  upon  these  frames  panels,  large  and  small, 
rest  and  slide,  which  are  easily  handled  under  all  circumstances. 

But  as  this  dam  is  situated  in  a branch  of  the  Seine  which  is  not 
navigable,  and  behind  the  sci'eens  for  protecting  the  water  wheels 
which  form  the  Marly  machine,  the  frames  are  never  lowered  as  in 
movable  dams,  for  no  boat  ever  passes  through  it;  and  as  the  screens 
protect  it  completely  from  ice,  it  is  sufficient  to  vary  the  flow  over  the 
weir  as  the  waters  rise  or  fall.  These  frames  being  thus  fixed,  and 
incapable  of  being  lowered,  certain  modifications  in  their  construc- 
tion have  been  mad»,  economizing  material  used,  and  changing  the 
system  of  attachment  to  the  flooring,  both  of  which  have  been  here 
introduced  for  the  first  time. 

The  dam  is  36.15  meters  wide  and  has  a fall  of  3 meters.  The 
flooring  is  placed  0.20  meter  above  the  lower  bay.  The  frames  are 
twenty -eight  in  number,  1.25  meters  apart;  the  dam  is  closed  by 
panels,  large  and  small,  sliding  in  guides  formed  by  the  upstream 
uprights  of  the  frame,  and  handled  by  a windlass  rolling  on  the 
service  bridge. 

(40)  Flooring.— The  flooring.  12  meters  long,  between  two  rows  of 
piles  and  sheet  piling,  is  3.75  meters  thick,  consisting  of:  (1)  A layer 
of  beton  2 meters  thick,  laid  under  water,  and  covering  the  heads  of 
210  piles,  driven  to  consolidate  the  foundations;  (2)  of  a mass  of 
rough  masonry  1.30  meters  thick;  (3)  a hewn  stone  revetment  0.45 
meter  thick. 

The  rear  apron,  4.50  meters  long,  is  formed  of  masonry  blocks,  2.250 
cubic  meters,  weighing  about  5,000  kilograms  each;  and  at  the  end 
of  these  blocks  coarse  riprap  is  placed. 

This  dam  was  constructed  by  means  of  a cofferdam  built  above, 
having  a fall  of  3.20  meters.  Below,  the  work  was  sheltered  from 
little  freshets  by  simply  raising  the  inclosing  walls,  which  were  sawn 
away  when  the  frames  had  been  set  up. 

(41)  The  frames. — The  fixed  frames  are  3.80  meters  high  and  3 
meters  long  at  the  base  (Fig.  9).  The  upstream  upright,  inclined  at 
an  angle  of  22°  30’,  with  the  vertical,  directs  the  resultant  pressure 
towards  a point  exterior  to  the  base  but  very  near  the  downstream 
end;  the  overturning  moment  is  nearly  nothing,  and  the  general 
action  of  the  frame  upon  its  fastenings  is  reduced  nearly  to  a hori- 
zontal thrust.  The  pressure  is  transmitted  directly  to  the  apron  by 
three  inclined  braces,  which  divide  it  between  the  different  groups 
of  fastenings,  so  that  these  fastenings  only  resist  shearing. 


CIVIL  ENGINEERING,  ETC. 


571 


Nevertheless,  to  guard  against  the  vertical  tension  from  below  up- 
ward the  first  anchorage  consists  of  a great  cut  stone,  attached  to 
the  mass  of  the  apron  by  channel-iron  plate  bands  and  anchor  rods 
2.50  meters  deep,  with  washers  0.40  meter  in  diameter. 

Each  frame  rests  upon  the  horizontal  surface  of  the  apron,  on  its 
lower  flange,  forming  a double  T reversed,  and  strengthened  by  a 
plate,  the  whole  having  the  form  shown  in  Fig.  10.  It  is  fastened 
by  eight  bolts  divided  into  four  groups,  and  a cast-iron  shoe  placed 
on  the  downstream  side,  fastened  by  three  bolts  0.03  meter  in  diam- 
eter. 


Fig.  9.  Fixed  frame  used  in  the  Marly  Dam. 


Fig.  10.  Method  of  anchoring  the  frame. 


The  total  maximum  pressure  of  9,579  kilograms  gives  a horizontal 
component  of  8,850  kilograms,  and  if  we  admit  that  the  lower  flange 
of  the  frame  divides  this  effort  equally  between  all  the  fastenings— 
which  is  a rational  supposition  in  view  of  the  situation  of  the  braces, 
and  the  rigidity  of  the  lower  flange — we  find  that  each  bolt  has  a 
load  of  805  kilograms,  that  is,  a maximum  load  of  2.05  kilograms 
per  square  millimeter  of  section. 

The  weight  of  each  frame  is  G.35  kilograms. 

(42)  The  panels  are  3 meters  high  vertically  and  3.25  meters  in  the 
direction  of  the  uprights  of  the  frames.  They  are  divided  into  four 
ranks,  having  the  following  heights,  respectively,  0.89,  0.98,  1.09, 
and  0.32  meters.  The  last  rank  serves  to  regulate  the  fall.  In  each 
rank  the  thickness  of  the  panel  varies  from  the  base  to  the  summit, 
so  as  to  avoid  all  useless  weight. 

These  panels  can  be  handled  from  the  upper  service  bridge  by 
means  of  a windlass  of  1,800  kilograms  power,  which  can  raise  a 


572 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


panel  from  the  bottom  or  drive  it  back  under  a fall  of  3.80  meters,  a 
fall  higher  than  would  be  possible  under  any  circumstances. 

The  upper  panels  are  moved  by  a little  crane  of  300  kilograms 


power,  more  easily  handled  than  the  windlass. 

(43)  Cost.— The  cost  amounts  to  271,000  francs,  as  follows: 

Francs. 

Upstream  cofferdam,  60  meters  long,  built  in  a fall  of  from  1.50  to  2 meters  . 55, 000 

Dredging  foundations  in  the  location  of  those  of  the  old  Marly  machine  . . 30,000 

Wood  and  masonry  work  for  flooring  and  abutments 133,000 

Storehouse  and  removal  of  the  cofferdam  24, 000 

Iron  frames',  panels,  windlass,  etc 22,000 


Total 271,000 


Price  per  running  meter,  7,490  francs. 

The  work  were  directed  by  M.  Boult?,  chief  engineer,  and  M.  Jozan, 
assistant  engineer. 

Chapter  IV.— The  new  lock  at  Bougival  and  its  hydraulic 
WORKING  APPLIANCES. 

Looking  up  the  stream  on  the  right  is  the  famous  Marly  machine, 
a collection  of  water  wheels  for  supplying  the  city  of  Versailles  with 
water;  at  right  angles  to  it  is  the  new  dam,  N,  at  Marly  (see  Fig.  11). 
A is  its  waste  weir;  on  the  left  is  Loge  Island,  on  which  a roadway  is 
built  at  a reference,  26.80  meters  above  sea  level,  connected  by  a foot- 
bridge with  the  right  bank.  Next  on  the  left  is  a great  lock,  G,  con- 
necting the  two  pools,  Bezons,  23.73  meters,  and  Andresy,  20.53 
meters.  To  the  left  is  the  little  lock,  P.  Two  houses  for  the  lock- 
men,  E E,  are  situated,  one  on  Loge  and  the  other  on  Gauthier 
Island. 

(44)  The  work  of  constructing  new  locks  at  Bougival  for  the  pur- 
pose of  obtaining  a draft  of  3.20  meters  between  Paris  and  Rouen 
was  begun  in  1879  and  finished  in  1883. 

Two  locks,  side  by  side,  have  been  built,  one,  220  meters  long  and  ■ 
17  meters  broad,  for  trains,  and  the  other,  41.00  meters  long  and  80.20 
meters  broad,  for  isolated  boats.  Both  locks  accommodate  boats 
drawing  3 meters.  The  fall  is  3.20  meters. 

The  length  of  the  great  lock  was  made  220  meters,  instead  of  140 
meters  the  usual  size  on  the  lower  Seine,  in  order  that  it  might  con- 
tain the  largest  trains  which  the  towing  company  generally  tows 
between  St.  Denis  and  Paris,  that  is  to  say,  sixteen  or  seventeen 
barges  and  the  towboat. 

(45)  Motive  power — All  the  apparatus  of  the  locks  except  the 
gate  sluices  are  worked  by  water  power,  from  an  accumulator  loaded 
so  as  to  produce  a pressure  of  00  atmosphei’es  and  supplied  by 
pumps  driven  by  turbines  obtaining  their  power  from  the  Marly 
dam. 


CIVIL  ENGINEERING,  ETC. 


573 


The  motive  for  adopting  this  apparatus  was  the  great  traffic  pass- 
ing through  these  locks,  which  are  the  most  frequented,  not  only  of 
the  lower  Seine,  but  of  the  navigable  water  ways  of  France.  There 
passed  in  1888  through  the  Bougival  locks  23,230  boats,  carrying 
3,050,829  tons  of  merchandise. 


Before  describing  the  new  locks  we  must  add  that  the  old  Bougival 
lock  constructed  in  1838  by  M.  Poirde  has  just  been  restored,  giving 
a chamber  113.50  meters  of  available  length  and  12  meters  wide, 
capable  of  containing  six  barges  drawing  2.30  meters. 


574 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


(46)  Netv  locks. — The  coping  of  the  new  locks  is  placed  1.G1  meters 
above  the  normal  height  of  the  upper  bay,  which  is  the  height  corre- 
sponding to  the  highest  water  safely  navigable  Avith  the  towboat. 

The  gates,  12  meters  wide  for  the  large  lock  and  8.20  meters  for  the 
small,  are  of  pitch  pine  with  oak  frames.  Each  pair  of  lea\res  has 
four  gridiron  valves  having  a total  section  of  3.4;}  square  meters. 

Besides  these  valves,  culverts,  placed  in  the  Avails  on  each  side  of 
the  gate,  fitted  with  gridiron  sluices,  have  a total  sectional  area  of 
4.80  square  meters  for  the  large  lock  and  3.50  square  meters  for  the 
small. 

The  volume  of  Avater  requisite  for  each  lockage  is,  respectively, 
13,800  and  1,750  cubic  meters. 

(47)  Hydraulic  machinery. — The  application  of  hydraulic  poAver 
for  working  the  neAv  locks  at  Bougival  according  to  the  plans  of  M. 
Barret  Avas  decided  on  in  1879.  The  system  includes:  (1)  The  ma- 
chinery and  accumulator;  (2)  the  piping;  (3)  the  hydraulic  presses 
for  moving  the  gates,  cuh'erts,  sluices,  and  capstans. 

The  machinery  and  accumulator  are  placed  in  a building  on  the 
right  abutment  of  the  Marly  dam  and  comprise: 

First.  Tavo  Fontaine-Baron  turbines  Avorked  by  the  fall  of  the 
Marly  dam  which  varies  from  2.30  meters  to  0.80  meter  and  gh'es 
under  the  least  favorable  condition  14  horse  power. 

Second.  Tavo  sets  of  three  single-acting  plunger  pumps  dri\ren  by 
the  turbines  by  means  of  beveled  gearing,  capable  of  making  from 
twenty-three  to  forty-five  strokes  per  minute  and  forcing  into  the 
accumulator  from  1.372  to  2.205  liters  per  second.  A pump  is 
attached  to  each  turbine  to  raise  water  for  the  tank  on  the  first  story, 
which  supplies  the  Avater  for  the  accumulator.  * 

Third.  An  Armstrong  accumulator  of  700  liters  capacity  loaded 
for  a pressure  of  60  kilograms  per  square  centimeter.  Its  stroke  is 
5 meters,  and  it  is  filled  in  from  4 to  9 minutes, 

The  piping  comprises  the  supply  pipe  from  the  accumulator  to  the 
hydraulic  machinery  on  the  lock  Avails,  and  the  pipe  which  returns 
the  Avater  to  the  feeding  tank;  so  that  the  same  water  constantly  cir- 
culates, except  some  slight  losses  which  are  made  good  by  the  pumps. 
The  pipes  are  cast  iron  or  drawn  wrought  iron;  those  Avhicli  have  to 
sustain  pressure  are  tested  up  to  a hydrostatic  pressure  of  110  kilo- 
grams per  square  centimeter. 

The  head  Avails  are  reached  by  means  of  siphons  submerged  in  the 
gate  chambers. 

The  effective  pressure  in  the  pipes  is  transmitted  to  a distance  of 
more  than  600  meters  from  the  accumulator  Avithout  loss  of  head  on 
account  of  the  slight  flow  and  the  small  diameter  of  the  pipe,  which 
is  only  from  0.0G  to  0.07  meter  in  interior  diameter. 


575 


576 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


NEW  LOCK  AT  BOUGIVAL. 


1 Pil 





Fio.  13. —Machinery  house  and  accumulator,  horizontal  section. 


'Hk! 


577 


CIVIL  ENGINEERING,  ETC. 


LOCK  AT  BOUGIVAL. 


H.  Ex.  410 — vol  hi 37 


578 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


LOCK  AT  BOUGIYAL. 


Apparatus  for  operating  the  lock  sluices  by  hydraulic  power  alone. 


Fig.  15.— Vertical  section.  Fig.  16.—  Elevation. 


CIVIL  ENGINEERING,  ETC. 


579 


LOCK  AT  BOUGIVAL. 

ApPARATVS  FOR  OPERATING  THE  LOCK  SLCICES  BY  HYDRA  L'LIC  POWER  ALONE. 


Fig.  17. -Horizontal  section  along  A,  B,  C.  D.  (Fig.  13)  Fig.  IS.- Plan  of  the  sluice. 


FIGS.  12,  13.  14. — Machinery  house  and  accumulator. 

a,  Supply  pipe  from  the  tank  to  the  pumps. 

b,  Direct  supply  pipe  for  the  pumps. 

c,  Supply  pipe  from  the  accumulator  to  the  presses. 

d,  Return  pipe. 

e,  Waste  valve  regulated  by  the  stroke  of  the  accumulator. 

/,  Lifting  pump ; g.  its  suction  pipe. 

Ii.  Pipe  supplying  the  accumulator. 

F.  Filter:  R,  reservoir;  i,  float. 

k.  Waste  pipe:  rr,  stopcocks:  s,  safety  valve. 

M,  T.  Punching  machine  and  lathe. 

V,  Turbine  sluices. 
v,  Emptying  cock  for  the  pipes. 

Figs.  15-18.— Apparatus  for  operating  the  lock  sluices. 

a.  Frame  of  the  cylinder  for  operating  the  sluices:  b.  Cylinder  for  operating  the 
sluices:  c,  Differential  piston;  d.  piston  rod:  e. air  cock;  //,  Water  cocks:  g,  gridiron 
sluice;  li,  sluice  seat;  j.  Upper  bearer;  k,  valve  chest. 


580  UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 

LOCK  AT  BOUGIVAL. 

Combined  apparatus  for  operating  tue  lock  sluices  either  by  hand  or  by  hydraulic  power. 


Fig.  *!.  -Engaging  gear 


CIVIL  ENGINEERING,  ETC. 


581 


LOCK  AT  BOUGIVAL. 

Figs.  13-23. — Apparatus  for  operating  by  hand. 

A,  Endless  screw  terminated  above  by  a square  head  on  which  a strong  kev, 
provided  with  handspikes,  fits. 

B,  Vertical  cylinder  for  operating  the  abutment  sluice. 

C,  Worm  wheel  driven  by  the  endless  screw  and  driving  the  rack  and  pinion; 
E E,  racks. 

F,  Balance  beam  driven  by  the  racks  and  united  in  the  middle  of  the  sluice. 

G,  Rollers  guiding  the  racks;  P,  counterpoise  counterbalancing  the  endless 
screw  to  facilitate  the  working  of  the  engaging  and  disengaging  gear. 

Hydraulic  apparatus  for  operating  the  lock  gates. 


Fig.  24.- Valve  chest,  vertical  section  along  I J (Fig  25). 


Fig.  25.— Horizontal  section  along  K L (Fig.  24). 

a,  Cast-iron  frame;  b,  bronze  valve  seat;  c,  valve  chest;  d,  D valve;  e,  valve  rod; 
f,  eccentric;  g,  eccentric  rod  having  its  vertical  axle  with  a square  end  to  fit  the 
operating  key;  i,  the  stem  of  the  stop  valve,  forming  the  valve  itself:  j,  duct 
leading  the  water  under  the  piston:  k,  exhaust;  /,  duct  leading  the  water  above  the 
piston;  m,  supply  pipe  for  the  water  under  pressure. 


582 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


LOCK  AT  BOUGIVAL. 


CIVIL  ENGINEERING,  ETC. 


583 


(48)  Protection  against  frost.  —In  the  winter,  to  avoid  frost  in  the 
apparatus  and  in  the  pipes  exposed  to  the  air  in  short  lengths,  6 or  8 
kilogrammes  of  glycerine  per  cubic  meter  are  added;  this  material 
has  the  advantage  of  lubricating  the  surface  of  the  pistons,  while 
chloride  of  magnesium,  though  cheaper,  corrodes  them  and  is  hard 
to  preserve  on  account  of  its  deliquescent  properties. 

When  the  apparatus  is  well  guarded  by  manure,  glycerine  is  only 
used  when  the  temperature  descends  7 or  8 degrees  below  freezing. 

(49)  On  the  supply  and  return  pipe  four  pieces  of  apparatus  are 
placed  for  operating  the  gates  of  the  large  lock,  each  consisting  of 
a horizontal  cylinder  (Figs.  20  and  27)  oscillating  around  a vertical 
axis  and  having  its  piston  attached  to  the  upper  transverse  girder  of 
the  leaf,  2 meters  from  the  heel  post;  this  piston  is  called  differential, 
because  in  one  direction,  the  pressure  being  the  same  on  the  two  faces 
of  the  piston,  the  motion  is  due  only  to  the  difference  of  the  sections 


Fig.  28.— Transverse  section 
through  X Y (Fig.  27). 


Fig.  29.— Section  parallel  to  X Y through  L (Fig.  27). 


on  which  the  pressure  acts.  This  pressure  acts  constantly  upon  the 
face  next  the  gate,  that  is,  upon  the  annular  face;  the  other  face, 
which  corresponds  to  the  total  section  of  the  cylinder,  is  put  alter- 
nately in  communication  with  the  accumulator  and  the  return  pipe. 

The  piston  is  attached  to  the  gate  by  a double  nut  which  can  be 
raised  while  in  use  to  prevent  the  former  from  bending,  and  its  eye  is 
oval  shaped  to  allow  for  the  transverse  displacement  of  the  leaves  in 
their  various  positions. 

The  breech  of  the  cylinder  rests  on  an  iron  guiding  sector.  Finally 
the  piston  stroke  exceeds  by  2 centimeters  its  requisite  geometric 
length,  so  as  to  take  into  account  the  possible  deflections  of  the 
leaves. 

This  apparatus  is  lodged  in  a pit  3. 50  meters  long,  0.85  meter  wide, 
and  0.46  meter  deep,  just  below  the  coping.  It  is  capable  of  exer- 
cising a tensile  effort  of  6,600  kilograms  on  the  piston  rod  to  open  a 


584 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


leaf,  and  a compressive  effort  of  4,710  kilograms  to  close  it.  Tlie 
dimensions  are  as  follows: 

Meters. 


Diameter  of  the  piston 0. 155 

Diameter  of  the  piston  rod 0. 100 

Maximum  stroke 2.520 


Water  expended  in  a double  stroke,  47.5  liters. 

Each  apparatus  has  on  its  supply  pipe  a cock  to  cut  off  the  water; 
at  the  bottom  of  the  cylinder  a waste  air  cock;  also  two  cocks  for 
emptying  the  cylinder  in  case  of  need. 

(50)  The  apparatus  for  the  small  lock  consists  also  of  four  pieces 
similar  in  every  respect  to  those  of  the  large  one. 

Meters. 


Diameter  of  the  piston 0. 128 

Diameter  of  the  piston  rod 0. 080 

Maximum  stroke 2. 060 


Water  expended  in  a double  stroke,  26.5  liters. 

This  apparatus  is  capable  of  exerting  on  the  piston  rod  a tensile 
effort  of  4,710  kilograms  to  open  the  gates,  and  a compressive  effort 
of  3,016  to  close  them. 

(51)  The  apparatus  for  operating  the  culvert  sluices  for  filling 
and  emptying  the  loch  chamber  are  eight  in  number,  consisting  of 
cylinders  with  differential  pistons  having  a stroke  of  0.55  meter  and 
acting  directly  on  the  gridiron  sluices,  capable  of  exerting  a tensile 
effort  of  8,244  kilograms  for  raising  the  sluices, and  a compressive 
effort  of  3,816  to  close  them. 


CIVIL  ENGINEERING,  ETC. 

Hydraulic  capstan  for  new  lock  at  bovgival. 


585 


5S6 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


Hydraulic  capstan  for  new  lock  at  Bocgival. 


Ftc.  32.— Plan  (cover  removed) 


CIVIL  ENGINEERING,  ETC. 


587 


(52)  The  ten  hydraulic  capstans  (Armstrong  type  modified  by  M. 
Barret)  placed  on  the  side  walls  of  the  great  lock  can  exert  a tractive 
effort  of  12,000  kilograms  on  a cable,  at  a velocity  of  0.43  meter 
per  second  (about  7 horse  power). 

All  these  pieces  of  apparatus  are  so  arranged  that  they  can  be  dis- 
connected (in  case  of  failure  of  the  water  supply,  or  for  any  other 
reason!  and  worked  independently  by  hand  (Figs.  19,  20). 


Fig.  33.— Lateral  elevation  along  I J (Fig.  31). 

Since  these  hydraulic  appliances  were  set  up  in  1883,  there  have 
been  only  three  insignificant  interruptions  in  their  regular  working, 
and  no  hindrance  has  occurred  in  the  navigation;  and  in  virtue  of 
the  precautions  taken  to  guard  the  pipes  and  presses,  there  has  never 
been  any  interruption  in  the  service  on  account  of  frost. 


Fig.  34.— Cross  section  through  the  valve  chest. 

(53)  Advantages  of  the  system. — The  lock  chamber  of  the  great  lock 
at  Bougival  can  contain  sixteen  or  seventeen  barges  with  their  tow- 
boat, and  the  time  of  lockage  is  thus  made  up:  Entrance,  arrange- 
ments, and  securing  the  boats,  20  to  25  minutes;  closing  the  gates,  30 
seconds;  filling  the  lock  chamber  (13,800  cubic  meters),  15  minutes; 
opening  the  gates,  30  seconds;  unfastening  and  hauling  out  the  boats, 
15  minutes. 

We  see  that  for  the  largest  train  which  the  lock  can  contain,  and 
which  may  carry  4,500  tons,  the  total  duration  of  the  process,  from 
the  time  of  entrance  of  the  towboat  to  the  exit  of  the  last  boat,  is  50 
minutes,  and  that  of  this  time  40  minutes  are  taken  up  in  the  en- 
trance and  exit  arrangements. 


588 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


The  small  lock  can  pass  eight  boats  per  hour.  The  traffic  in  1888 
through  the  Bougival  lock  exceeded  3,000,000  tons,  and  the  appliances 


would  serve  for  twice  that  amount. 

(54)  Cost. — The  total  cost  is  as  follows: 

Francs. 

Cost  of  land  damages 164, 942. 41 

Earthwork  and  masonry  for  the  cut-offs  and  locks 3,240,000.00 

Four  pairs  of  gates  72, 318. 64 

Stockades  above  and  below  the  locks 20, 000. 00 

Hydraulic  appliances 277, 087. 50 

Total 3,774,330.55 


The  annual  cost  of  working  the  hydraulic  appliances  is  about  7,200 
francs. 

(55)  Conclusions. — From  a thorough  examination  of  the  working 
of  these  hydraulic  appliances  we  may  conclude  : 

First.  That  the  introduction  of  hydraulic  appliances  in  the  great 
lock  at  Bougival  constitutes,  in  respect  to  operating  by  hand  or  by 
horse  power,  a considerable  improvement,  without  which  this  lock 
would  be  very  inconvenient,  and  limited  to  a traffic  of  about  3,000,000 
tons  per  annum,  while  this  figure  was  exceeded  in  1888. 

Second.  That  the  cost  of  establishment  and  maintenance  is  com- 
pensated by  an  economy  nearly  equal  in  amount  made  by  the  boat- 
men, so  that  in  a general  point  of  view  these  appliances  are  advan- 
tageous, since  they  allow  without  increase  of  cost  the  working  of 
the  locks  with  a traffic  of  5,000,000  or  6,000,000  tons,  while  the  ordi- 
nary appliances  would  not  suffice  for  the  transit  of  such  a tonnage. 

These  works  were  directed  by  M.  Boul6,  chief  engineer,  and  De 
Preaudeau,  assistant  engineer.  The  hydraulic  appliances  were  con- 
structed by  the  Fives-Lille  Co. 

Figs.  12-33,  inclusive,  are  taken  by  permission  from  the  Porte- 
feuille  des  Ponts  et  Chauss^es. 

Chapter  V. — New  movable  dam  at  Poses  on  the  Seine. 

(56)  The  movable  dam  at  Poses  on  the  Seine,  202  kilometers  below 
Paris,  is  the  most  important  of  those  recently  constructed  between 
Paris  and  Rouen  to  realize  at  all  times  a minimum  draught  of  3.20 
meters.  In  virtue  of  its  exceptional  height,  it  maintains  this  draught 
in  a bay  extending  from  Poses  to  Notre  Dame-de-la-Garenne,  a dis- 
tance of  41  kilometers,  while  the  average  length  of  the  other  bays 
is  only  23  kilometers  in  the  canalized  portions  of  the  river  between 
Paris  and  Rouen. 

In  the  preliminary  project  for  the  works  requisite  to  give  a min- 
imum draught  of  3.20  meters  to  the  lower  Seine,  it  was  proposed  to 
erect  at  Poses  a Poir^e  dam  having  a height  of  4 meters  above  the 
sill ; but  even  this  would  be  insufficient  to  cover  the  shoals  of  la 
Mare  and  Tosny,  without  requiring  excessive  dredging,  and  a second 


CIVIL  ENGINEERING,  ETC. 

Movable  dam  at  Poses  on  the  Seine.  Uprights  and  curtains  for  the  weirs. 


589 


- 

1 

j°5' 

.! . 

' 

i 

• 

*u 

u 

Fig.  35.— Longitudinal  section  in  front  of  the  uprights,  along  the  line  A B,  Fig.  36. 


590 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS, 


Fig.  36.- 


Fig.  39.— Chain  stop 


Uprights  and  cu  rtains  for  the  weirs.  Movable  dam 
at  Poses  on  the  Seine. 


Fig.  38. 


Fig.  37. 


Curtain  windlass. 


Elevation. 


Section. 


CIVIL  ENGINEERING,  ETC. 


591 


dam  with  a fall  of  1 meter  was  provided  for,  near  Andd,  10  kilome- 
ters above  Poses. 

The  new  dam  invented  by  M.  Camera  raises  the  upper  bay  at  Poses 
to  5 meters  above  the  sill,  and  thus  dispenses  with  the  proposed  work 
at  And£. 

Plate  IV  shows  an  admirable  model  of  part  of  the  Poses  dam, 
which  was  exhibited  in  the  Pavilion  of  Public  Works. 

Before  entering  into  details  it  will  be  well  to  indicate  in  a general 
manner  the  principles  and  mode  of  working  this  new  type  of  dam. 


Camere's  curtains. 


Flos.  40,41. — Details  of  the  curtain  hinges  and  shoe,  cross  section  and  elevation. 


Figs.  35-40  show  the  construction  of  Camera's  curtains  and  their 
method  of  suspension.  The  curtains  themselves  consist  of  wooden 
battens,  hinged  together  (Figs.  40,  41)  and  resting  against  vertical 
supports;  these  supports  are  suspended  from  a bridge,  shown  in  Figs. 
42-48.  Figs.  37  and  38  show  the  construction  of  the  windlass  for 
handling  the  curtains. 


592 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


(57)  The  jointed  curtain  consists  of  a series  of  wooden  bars  (Figs. 
35  and  36)  arranged  horizontally,  one  above  another,  resting  against 
the  vertical  supports  of  the  dam ; the  bars  have  a constant  height, 
but  their  thickness  varies  with  the  head  of  water  they  have  to  sus- 
tain ; they  are  joined  together  by  two  rows  of  hinges  on  their  up- 
stream side.  (Figs.  40  and  41).  A specially  constructed  piece  is 
hinged  to  the  lowest  bar ; this  piece  rests  upon  the  flooring  of  the 
dam  when  the  curtain  is  unrolled,  and  forms  the  center  piece  when 
the  curtain  is  rolled  up.  It  is  called  the  rolling  shoe  ; it  is  cylindri- 
cal in  form,  having  for  its  base  half  the  spire  of  an  Archimedian 
spiral ; the  upper  surface  of  the  shoe  is  plain,  and  surmounted  by 
three  flanges  whose  contour  forms  the  second  half  of  the  spire  of  the 
same  spiral. 

The  curtain  is  suspended  by  hooks  fastened  above  the  water  to  the 
fixed  portions  of  the  dam,  by  two  chains  attached  to  a ring  bolted  to 
the  upper  bar  in  line  with  the  two  rows  of  hinges ; it  is  moved  by  an 
endless  chain  worked  by  a special  windlass.  This  chain  descends  on 
the  downstream  face  of  the  curtain,  passes  under  the  shoe  and  ascends 
along  the  upstream  face.  The  two  ends  prolonged  abovethe  curtain 
are  carried  by  fixed  guide  pulleys  to  the  curtain  windlass. 

The  windlass  is  so  arranged  that  for  rolling  up  the  curtain  the  two 
chains  move  together.  The  upstream  chain  rises,  while  the  down- 
stream chain  falls,  but  with  different  velocities;  the  upstream  chain 
moving  faster  than  the  other,  so  that  the  chain  slides  under  the 
shoe  ; the  resulting  friction  added  to  the  traction  of  the  chain  itself 
causes  the  shoe  to  turn  about  its  axis,  and,  successively,  all  the  bars 
about  their  hinges,  thus  rolling  up  the  curtain  from  below.  It  is 
rolled  up  wholly,  or  in  part,  so  as  to  open  wholly  or  in  part  the  aper- 
ture which  it  closed.  To  unroll  the  curtain,  the  upstream  chain  is 
let  go,  and  the  downstream  chain  made  fast. 

When  the  lengths  of  the  suspending  chains  are  properly  regulated 
so  as  to  make  the  upper  bar  horizontal,  the  curtain  rolls  and  unrolls 
between  two  vertical  planes  ; but  to  avoid  any  error  arising  from  de- 
fective construction  or  regulation,  it  is  found  best  to  have  the  cur- 
tain guided,  so  as  to  prevent  lateral  deviation.  In  the  first  applica- 
tion of  this  system  to  the  Villier  dam,  the  ends  of  the  bars  resting 
on  the  upstream  face  of  the  frames  were  guided  by  a small  flange 
on  that  face.  At  Poses,  two  rows  of  little  angle  irons  are  fixed  to  the 
downstream  bars ; one  side  of  the  angle  iron,  projecting  from  the 
bar,  strikes  against  the  side  of  the  upright  supports  in  case  of  the 
lateral  displacement  of  the  curtain.  To  avoid  obstruction  in  rolling, 
these  angle  irons  are  only  placed  on  the  outer  spiral  so  that  the  cur- 
tain is  only  guided  for  half  its  height,  but  that  is  sufficient  owing 
to  its  transverse  stiffness. 

Since  the  guidance  of  the  curtains  is  assured  without  making  use 
of  the  ends  of  the  bars,  the  curtain  may  be  prolonged  beyond  the  up- 


Paris  Exposition  of  1889 — Vol.  3.  Civil  Engineering,  etc. — PLATE  IV 


MODEL,  BY  REYNARD  BROTHERS  OF  PARIS,  OF  A PORTION  OF  THE  DAM  AT  POSES. 


distinguish  them  from  those  which  only  close  one  span.  It  may  be 
observed,  that  in  consequence  of  the  bars  projecting  over  the  sup- 
ports, they  resist  as  if  they  were  built  in  from  these  points,  and  con- 
sequently need  not  be  stronger  than  the  bars  of  the  simple  curtain. 

H.  Ex.  410— vol  in 38 


CIVIL  ENGINEERING,  ETC.  593 

rights  of  the  successive  frames  so  as  to  project  over  half  the  opening 
between  the  succeeding  frames,  its  width  thus  corresponding  to  that 
of  two  successive  spans,  so  that  it  can  in  no  case  be  carried  obliquely 
between  the  uprights.  These  latter  curtains  are  called  double,  to 


Movable  dam  at  Poses  on  the  Seine  Upper  bridges  of  the  non  navioable  passes. 


504 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


(58)  Suspending  bridge. — Figs.  42-48  show  the  sectional  plan,  two 
elevations,  and  details  of  the  suspending  and  hoisting  bridge.  The 
aperture,  shown  in  the  plan,  is  for  hauling  the  curtains  through, 
endwise,  when  they  are  to  be  taken  off  and  stored  or  repaired. 


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The  suspending  bridge  (Figs.  4*2,  45  and  48)  is  made  up  of  two 
lattice  girders,  supporting  a roadway  and  resting  on  piers.  It  is 
placed  high  enough  to  allow  sufficient  space  under  the  lifted  frames 
for  an  easy  flow  of  the  waters  of  a freshet,  and  in  the  navigable 
passes  a free  height  sufficient  for  the  passage  of  boats  when  the  dam 
is  open. 


CIVIL  ENGINEERING,  ETC. 


595 


The  frames  used  to  support  the  curtain  are  suspended  by  joints 
to  the  roadway  ; they  are  formed  of  uprights  braced,  and  having 
their  lower  ends  resting  against  square  stone  posts  anchored  in  the 
flooring  and  leaving  a play  between  it  and  the  feet  of  the  uprights  ; 
their  upper  extremities  rest  against  brackets  built  for  that  pur- 
pose just- below  the  principal  girders.  (Fig.  30). 

The  open  spaces  between  the  frames  are  closed  by  the  double  cur- 
tains above  described,  with  horizontal  bars  extending  from  the 


Fig.  48.— Dam  at  Poses.  Longitudinal  section  along  I K (Fig.  42).  and  upstream  elevation  of  the  inter 

mediate  girder. 

middle  of  one  span  to  the  middle  of  the  second  span  beyond  it.  The 
windlass  for  handling  the  curtains  rolls  on  the  service  bridge, 
situated  on  the  downstream  side  of  the  uprights  and  supported  by 
them. 

This  bridge  is  formed  of  sections  corresponding  to  each  frame 
and  jointed  to  it  at  a distance  of  1 meter  above  the  upper  bay.  The 
roadway  of  the  bridge,  to  which  the  frames  are  suspended,  acts  like 
a horizontal  beam,  carrying  to  the  braces  on  the  piers  and  abutments 
the  pressure  of  the  water  transmitted  by  the  frames  to  their  upper 
support. 


596 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


(59)  Hoisting  bridge. — On  a second  bridge,  called  the  hoisting 
bridge,  a second  windlass  rolls,  which  can  be  hooked  successively  to 
each  of  the  frames  to  raise  or  lower  it. 

To  open  the  dam  the  curtains  are  rolled  up  above  the  water  level ; 
the  sections  of  the  service  bridge  are  folded  against  their  frames; 
then,  by  means  of  a windlass  on  the  hoisting  bridge,  the  frames  are 
raised  to  a horizontal  position  and  fastened,  so  that  the  pass  is  com- 
pletely free.  (Fig.  42). 

To  close  the  dam  the  operations  are  carried  on  in  an  inverse  order. 

Finally,  to  provide  for  the  eventuality  of  not  being  able  to  raise 
the  uprights  toward  the  upstream  side,  their  joints  are  placed  in  up- 
right guides,  which  allow  them  to  be  raised  to  a height  sufficient  to 
clear  the  hurter  ; the  frames  may  then  rotate  in  a downstream 
direction  and  be  raised  if  necessary  in  this  direction. 

(00)  Description  of  the  Poses  dam.  (See  map,  Fig.  49.  p.  59?). — On 
the  right  bank,  looking  downstream,  are  the  loekmen's  houses ; next, 
the  old  lock  and  dam  ; next,  the  little  lock,  c ; then  the  great  lock 
next  to  Mouchouette  Island,  from  which  a dike  223  meters  long  pro- 
jects up  the  river,  extending  beyond  Pointe  Island.  Between  Mou- 
chouette Island  and  the  left  bank  extends  the  new  Poses  dam,  or 
barrage,  with  the  raised  or  non-navigable  passes  at  the  right,  the 
weir  in  the  middle,  and  the  navigable  passes  at  the  left. 

The  Seine  is  here  divided  into  two  branches.  On  the  left  side  of 
the  cut-off  there  are  two  new  locks  built  side  by  side,  each  assuring 
a draught  of  3.20  meters.  The  old  lock  on  the  right  bank  could  not 
be  preserved  on  account  of  the  too  great  height  of  its  tail  miter  sill. 
These  locks  are  in  all  respects  like  those  heretofore  described,  typical 
Seine  locks. 

A jetty,  223  meters  long,  is  built  as  the  downstream  prolongation 
of  the  left  chamber  wall  of  the  large  lock;  it  facilitates  the  handling, 
shelters  the  barges,  and  protects  them  against  the  prevailing  winds 
and  the  currents  from  the  Poses  branch. 

Finally,  to  complete  the  closing  of  the  right  branch,  a part  of  the 
old  Poirde  dam  has  been  preserved,  having  its  sill  1.7C  meters  below 
the  present  upper  bay  level.  The  branch  on  the  left,  called  the 
Poses  branch,  is  closed  by  the  great  Poses  dam. 

(01)  New  principles. — With  the  new  system,  the  height  being 
no  longer  limited,  the  level  could  be  assumed  at  8.45  meters 
above  sea  level,  to  avoid  constructing  the  dam  projected  at  Amid  in 
the  preliminary  project. 

The  level  of  the  sill  of  the  navigable  passes  was  fixed  below  a line 
passing  through  the  tops  of  the  regulating  sills,  and  having  a de- 
clivity equal  to  the  mean  declivity  of  the  waters  of  the  river;  it  has 
thus  been  fixed  at  the  level  3.45  meters,  that  is,  5 meters  below  the 
upper  bay. 


CIVIL  ENGINEERING,  ETC. 


597 


The  situation  as  indicated  in  Fig.  49,  just  above  Pointe  Island, 
offers  two  advantages;  first,  proximity  to  the  locks  and  a satisfac- 
tory arrangement  to  all  parts  of  the  dam;  second,  a natural  sill  at 
the  elevation  of  3.05  meters,  that  is,  at  about  the  same  level  as  the 
projected  flooring. 


Fig.  49. — Map  showing  the  position  of  the  new  movable  dam  at  Poses. 


The  Poses  dam,  235.20  meters  between  the  abutments,  is  di- 
vided into  seven  passes ; five  deep  and  two  shallow  ones.  The  com- 
bination of  the  heights  of  the  sills  of  the  different  passes  was  made 
so  as  to  obtain  a sufficient  superficial  flow  by  uniting  as  well  as  pos- 
sible the  transverse  profile  of  the  river  at  the  right  with  the  chosen 
location.  The  dam  is  thus  divided  into  three  distinct  parts;  two 


598 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


corresponding  to  the  two  arms  surrounding  Pointe  Island,  and  the 
other  to  the  cross  section  of  the  island  itself.  The  sills  are  placed 
at  the  altitude  3.45  meters  above  tide  water  in  the  first  case,  and 
5.45  meters  in  the  second. 


(62)  Depth  of  foundation. — The  exceptional  height  of  the  dam  re- 
quired a foundation  to  be  laid  upon  a solid  and  impermeable  stratum, 
thus  avoiding  all  filtration  which  would  compromise  the  stability  of 


CIVIL  ENGINEERING,  ETC. 


599 


the  structure  and  absorb  a portion  of  the  flow  during  low  water, 
when  most  needed  for  navigation.  It  was  found  best,  as  in  the  case 


of  the  locks,  to  descend  to  a bank  of  solid  chalk  which  is  met  at 
about  5 meters  below  the  sea  level  for  the  whole  width  of  the  river 
bed. 


600 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


(G3)  Piers  and  abutments. — The  piers  are  4 meters  thick;  on  the 
downstream  side,  the  starlings  (Fig.  50)  project  a considerable 
amount  beyond  the  roadway,  and  support  masses  of  masonry  which 
rise  to  the  top  of  the  bridge;  these  masses  serve  to  resist  the  hori- 
zontal thrust  which  is  transmitted  by  the  suspended  frames  to  the 
bridge. 

The  piers  and  abutments  are  pierced  by  full  centered  arches  1.30 
meters  wide  and  2.30  meters  high,  so  as  to  allow  the  service  bridge 
to  be  freely  carried  through  them.  In  these  passages  niches  are 
made  to  store  the  curtains  and  windlasses. 

(04)  Flooring. — The  surface  of  the  flooring  is  plain,  at  the  level 
3.10  meters  above  the  sea  for  the  deep  passes,  and  5.20  meters  for 
the  shallow  ones.  This  surface  is  limited  on  the  upstream  side  by 
a sill  curved  up  just  above  the  level  of  the  hurters,  so  as  to  protect 
them  against  the  keel  of  any  boat  or  the  shock  of  bodies  against 
them. 

(05)  The  hurters  are  1.10  meters  apart,  built  into  the  flooring 
and  projecting  0.35  and  0.25  meter  above  it  in  the  deep  and 
shallow  passes  respectively.  They  are  protected  by  flanged  iron 
plates  fastened  to  them.  A bolt,  passing  horizontally  through  each 
stone,  is  secured  by  a nut  at  the  back.  This  bolt  is  also  secured 
to  1 lie  anchorage  bar  of  the  flooring  so  as  to  transmit  to  the  piers  the 
longitudinal  pressure  of  the  uprights.  The  hurters  rest  against  the 
plate  band  of  hewn  stone. 

To  increase  the  solidity  of  the  whole,  the  two  limiting  walls  of  the 
flooring  are  united  by  tie  rods  sunk  in  the  masonry  and  passing 
between  the  hurters. 

Finally,  a row  of  cast-iron  boxes  and  anchor  rings  have  been  sunk 
in  the  masonry  flooring  in  front  of  and  behind  the  hurters,  so  as  to 
permit  a cofferdam  to  be  rapidly  set  up  in  case  of  repairs. 

(00)  Upper  bridges. — The  system  adopted  at  Poses  requires  the 
establishment  of  two  upper  bridges,  according  to  the  idea  of  the  late 
M.  Tavernier. 

First.  The  downstream  bridge  to  hold  the  suspended  frames,  and, 
second,  the  upstream  bridge  to  hold  the  windlasses  while  the  frames 
are  being  raised,  and  also  sustain,  a part  of  the  weight  of  the  raised 
frames  themselves.  The  first  may  be  called  the  suspending,  and  the 
second  the  hoisting  bridge. 

The  roadways  of  the  two  are  for  two  different  purposes  and  at 
different  levels.  The  downstream  longitudinal  girder  of  the  hoist- 
ing bridge  is  omitted,  and  its  supporting  cross  girders  are  attached 
directly  to  the  longitudinal  upstream  girder  of  the  suspending  bridge, 
thus  affording  easy  communication  between  the  bridges,  and  adding 
to  the  horizontal  strength  of  both.  The  upstream  roadway  has  an 
opening  1.50  by  2.50  meters,  large  enough  to  admit  of  passing  the 
curtain  through  it  endwise.  (Fig.  45.) 


601 


CIVIL  ENGINEERING,  ETC. 


In  the  non-navigable  passes  the  facility  of  communication  is 
insured  by  putting  a third  roadway  above  the  beams  of  the  down- 
stream roadway. 


Fig.  52.— View  of  Poses  clam  from  above.  The  raising  of  a frame. 


The  lattice  girders  supporting  the  roadway  have  their  uprights 
2.32  meters  apart,  corresponding  to  the  widths  of  the  moving  parts. 


Fig.  58.— View  from  below.  The  rolling  of  a curtain. 


The  cross  girders  take  the  strain  of  the  hanging  frames  by  means  of 
the  brackets  arranged  under  them.  These  girders,  1. 16  meters  apart, 
are  braced  by  U irons  placed  on  each  side  of  the  rods  suspending  the 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


602 

frames.  The  brackets  are  trapezoidal  in  form,  0.G1  meter  high  (Fig. 
42).  Upon  each  of  their  faces  two  angle  irons  are  riveted,  project- 
ing on  each  side  and  forming  a guide  0.125  meter  wide.  The  heads 


at  the  end  of  the  suspending  bars  rest  upon  these  guides  at  a height 
0.50  meter  under  the  cross  girders,  so  that  the  uprights  can  be  raised 
to  the  flanges  of  these  girders,  that  is,  so  that  the  uprights  may  clear 
the  hurters  (Figs.  54  and  55). 


CIVIL  ENGINEERING,  ETC. 


603 


The  width  of  the  upstream  roadway  depends  on  its  height  above 
the  water.  There  must  be  space  enough  from  the  end  girder  to  the 
point  where  the  chain  comes  through  to  work  the  windlass,  also  to 
give  the  chain  a proper  inclination,  to  avoid  too  much  tension  on  it. 

At  Poses  the  chain  is  attached  to  the  frame  at  0.90  meter  below 
the  water  level,  and  the  chain  is  inclined  33  degrees  at  the  beginning. 
The  distance  between  the  principal  girders  of  the  upstream  roadway 
is  7.55  meters  for  the  navigable  passes  and  5.25  meters  for  the  lion- 
navigable. 

The  upstream  roadway  is  placed  halfway  up  the  principal  girder, 
so  as  to  allow  sufficient  space  below  the  cross  girders  to  store  the 
rolled  curtain  when  the  frames  are  raised. 

The  cross  girders  are  2.32  meters  apart,  united  by  stringers.  The 
beams  of  the  upper  bridges  rest  on  their  piers  and  abutments  by  a 
hinged  joint,  so  that  the  resultant  of  pressure  always  passes  through 
the  center  of  contact  whatever  may  be  the  deflection  of  the  beams 
themselves. 

Expansion  trucks  are  placed  vertically  between  the  downstream 
girder  and  the  massive  starling. 

(07)  The  uprights,  which  support  the  curtains,  are  wrought-iron 
beams  with  angle  irons,  having  their  mean  fibers  inclined  0.005  meter 
per  meter,  so  that  the  vertical  passing  trough  the  center  of  gravity 
of  the  frame  with  its  curtain  and  foot  bridge  is  on  the  upstream  side 
of  its  upper  joint.  The  uprights  have  a U-shaped  section  which  is 
constant  in  width  2.50  meters  above  the  upper  bay  for  the  same  pass; 
this  width  is  0.50,  0.00,  and  0.70  meter  for  the  three  passes  respect- 
ively. Above  this  level  the  width  tapers  to  0.25  meter  at  the  top. 

The  joint  of  the  uprights  with  the  suspending  shaft  is  made  by  a 
cast-steel  eye"  wedged  onto  the  shaft,  and  terminated  by  a cheek 
which  is  riveted  to  the  web  of  the  upright.  Lengthwise  the  uprights 
are  arranged  in  groups  of  two,  and  the  axes  of  these  groups  are  1.10 
meters  apart.  The  object  of  this  division  was  to  reduce  the  width  of 
the  moving  pieces  to  1.10  meters  in  case  the  length,  2.32  meters,  of 
the  curtains  should  be  found  too  great ; but  as  this  length  has  been 
found  convenient  the  arrangement  of  the  uprights  in  subsequent 
dams  of  this  type  has  been  simplified.  At  Port-Mort,  for  example, 
the  uprights  have  a double  ~f  section. 

(08)  Frames. — Each  frame  is  formed  of  four  uprights,  united  by 
ties  2 meters  apart  and  having  a width  0.15  meter  less  than  that  of 
the  upright,  so  as  to  afford  a passage  to  the  hoisting  chains  and  a 
lodgment  for  those  of  the  frames.  One  of  these  ties  is  on  the  level 
of  the  service  bridge,  and  upon  it  is  a cast-iron  box  which  holds  the 
slack  of  the  curtain  chains.  The  uprights  of  the  same  frame  are 
also  tied  by  three  shafts,  viz : first,  the  upper  suspending  shaft; 
second,  the  shaft  2 meters  above  the  service  bridge,  used  for  attach- 
ing the  hoisting  tackle  of  the  service  bridge;  and  third,  that  to  which 
the  hoisting  chains  of  the  frames  are  attached. 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


<>04 

(09)  'Hip  hoisting  chains. — There  are  two  hoisting  chains  for  each 
frame;  each  chain  divides  into  two  branches,  so  that  the  end  of  one 
branch  is  attached  to  each  upright,  thus  dividing  the  strain  of  lifting 
the  frame  into  four  equal  portions  (Fig.  35).  On  the  downstream 
side  of  the  uprights  a strong  wrought-iron  hook  with  angle  irons  is 
attached,  for  the  purpose  of  raising  the  frame  in  case  of  accident  to 
the  chains  or  to  their  attachments  (Fig.  30).  This  can  be  done  by 
lowering,  along  the  upright,  a chain,  the  bight  of  which  will  be  held 
securely  by  the  hook.  Ringbolts  are  attached  to  the  upstream  side 
of  the  uprights,  so  that  the  frames  may  be  slung  below  the  upper 
bridge  when  any  repairs  are  required. 

(70)  Method  of  suspending  the  frames. — The  method  adopted  for 
suspending  the  frames  has  been  somewhat  simplified  in  the  Port- 
Mort  Dam,  and  we  shall  here  give  the  method  employed  in  the  more 
recent  dam.  This  method  of  suspension  is  shown  in  Figs.  54  and  55. 
The  suspending  rods  are  terminated  by  cross-heads  fitted  onto  the 
rods  by  gibs  and  cotters ; these  wrought-iron  rods  have  a cross- 
shaped section  and  pass  between  the  braces  of  the  downstream  road- 
way, above  which  they  are  united  two  by  two  by  a cross  piece  having 
the  section  of  a double  T)  whose  extremities  can  slide  vertically 
between  the  uprights  of  two  cast-iron  chairs  bolted  to  the  roadway. 
In  their  normal  position  these  extremities  rest  on  chairs  by  means 
of  regulating  iron  wedges.  Similar  wedges,  placed  between  the  up- 
per face  of  the  crosspiece  and  the  upper  bearings  of  the  chairs  pre- 
vent the  frames  from  lifting. 

(71)  Foot  bridge. — The  foot  bridge,  made  up  of  framed  sections 
1.16  meters  longer,  is  constructed  of  U iron,  to  which  the  iron  floor- 
ing is  riveted  ; upon  this  flooring  the  rails  for  carrying  the  windlass 
are  laid.  The  upstream  side  of  the  section  is  hinged  to  the  down- 
stream side  of  the  uprights.  The  transverse  bars  of  the  section  are 
prolonged,  and  strike  against  corbels  riveted  on  the  webs  of  the 
uprights,  so  as  to  keep  the  sections  of  the  foot  bridge  horizontal 
when  it  is  lowered.  (Figs.  36  and  42.) 

(72)  Method  of  attaching  the  curtains.—  The  suspending  chains  are 
hooked  to  rings  attached  to  the  two  outside  uprights  of  each  frame 
at  1.25  meters  above  the  foot  bridge.  The  two  pulleys  for  rolling 
the  curtains  are  placed  between  the  intermediate  uprights.  The 
lower  pulley,  holding  the  downstream  chains,  is  slightly  smaller 
than  the  other.  This  inequality  insures  a distance  between  the  chains 
equal  to  the  thickness  of  the  first  curtain  bar.  Besides  rolling  the 
curtain,  each  side  of  the  endless  chain  can  be  fixed  upon  its  guide 
pulley  by  a stop  (Fig.  39),  carrying  a finger,  which  enters  the  link 
of  a chain  when  the  lever  is  lowered.  Finally,  the  uprights  have  on 
their  upstream  faces  iron  claws,  which  serve  as  stops  to  the  rolled 
curtain. 

(73)  Details  of  the  curtains. — Dimensions. — Each  curtain  corre- 


CIVIL  ENGINEERING,  ETC. 


005 


sponds  to  an  opening  2.32  meters  wide  and  5.35  meters  high  in  the 
deep  passes.  Tlie  bars  of  yellow  pine  are  all  0.078  meter  high,  with 
a play  of  0.002  meter  between  the  bars  to  allow  for  swelling  ; their 
length  is  2.28  meters,  giving  a play  of  0.04  meter  between  two  neigh- 
boring curtains ; this  interval  is  sufficient,  and  can  be  closed  by  a 
joint  cover  if  the  dam  reqires  to  be  made  tight. 

The  thickness  of  the  upper  bar  is  0.04  meter,  and  it  increases  pro- 
gressively downward  to  0.09  meter  for  the  deep  passes.  It  is  calcu- 
lated to  resist  a pressure  of  60  kilograms  per  square  centimeter. 
The  upper  bar,  exposed  to  shocks  from  floating  bodies,  is  strength- 
ened by  an  angle  iron. 

The  hollow  cast-iron  rolling  shoes  are  heavy  enough  to  cause  the 
curtain  to  sink  easily  into  the  water  when  unrolled. 

The  rows  of  hinges  form  a kind  of  chain  resisting  all  efforts  ex- 
erted on  the  chain  in  the  act  of  rolling.  These  hinges  are  of  bronze, 
so  as  not  to  rust;  they  have  strong  flanges,  and  their  axles  are  of 
drawn  phosphorus  bronze.  All  the  handling  machinery  can  be  car- 
ried on  cars  rolling  on  the  service-bridge  tracks. 

(74)  Windlass  for  handling  the  frames.  — The  maximum  effort 
which  can  be  produced  by  this  apparatus  is  at  the  termination  of  the 
lifting,  and  amounts  to  4,900  kilograms  for  the  deepest  passes.  This 
effort,  transmitted  by  the  chains  to  the  windlass,  is  exerted  by  four 
men  at  the  cranks,  or  by  a small  double-cylinder  steam  engine 
mounted  on  the  windlass.  A brake  serves  to  regulate  the  velocity 
of  the  descent  when  the  frames  are  lowered. 

(75)  To  raise  the  frames, — With  the  suspension  above  described 

and  in  use  at  Port-Mort  the  operation  is  as  follows:  Lifting  jacks, 

shown  in  Fig.  54,  are  placed  under  the  crosspieces  uniting  the  two 
suspending  rods  of  a frame  above  the  downstream  roadway.  Each 
jack  rests  upon  a platform  arranged  for  this  purpose  in  the  horizon- 
tal bracing  of  the  roadway.  After  placing  the  jack  and  removing 
the  wedges  which  prevent  the  lifting,  the  jack  is  screwed  up,  care 
being  taken  to  wedge  the  ends  of  the  crosspiece  as  it  moves  up;  this 
wedging  serves  to  sustain  the  lifted  frames.  The  chains  from  the 
windlass  on  the  upper  bridge  are  then  hooked  on,  and  the  frames  are 
rotated  to  a horizontal  position  and  made  fast  to  the  under  side  of 
the  upper  bridge. 

(76)  Execution  of  the  work. — The  foundations  were  laid  on  a bank 
of  chalk,  from  5 to  5.50  meters  below  the  sea  level.  Two  systems 
were  employed  ; first  a cofferdam  pumped  out  above  a layer  of 
beton  filled  in  an  inclosure  of  artificial  blocks  (for  the  abutment  on 
the  right  bank,  for  piers  Nos,  1,  2,  ?,  and  for  the  floorings  of  the 
passes,  Nos.  1,  2,  3,  and  4.). 

Second.  Foundations  in  caissons  by  compressed  air  for  piers  Nos. 

4,  5,  6,  the  abutment  on  the  left  bank,  and  the  floorings  for  passes 

5,  6,  7. 


UNIVERSAL  EXPOSITION  OK  1889  AT  PARIS. 


606 

The  surface  covered  by  the  foundations  of  the  Poses  Dam  and  its 
approaches  amounts  to  4,905.58  square  meters;  04,037  cubic  meters 
of  masonry  were  laid. 

(77)  Weight  of  the  iron  work. — Weight  of  the  iron  in  the  bridges 
and  frames,  1,316,991  kilograms;  weight  of  a curtain  with  its  chains 
for  the  deepest  passes,  911  kilograms;  weirs,  510  kilograms. 

The  final  project  was  approved  October  2G,  1878.  Work  on  the 
foundation  began  the  24th  of  May,  1880,  the  dam  was  completed  on 
the  24th  of  September,  1885,  and  lias  given  entire  satisfaction  since. 

(78)  Cost. — Cost  per  running  meter  : 


Francs. 

Masonry  foundations 13, 345 

Iron  work: 

U pper  bridges 1 , 87 1 

Frames 878 

Curtains,  etc 421 


Total 16,515 


The  project  of  the  Poses  Dam  was  drawn  up  by  M.  Camerd,  and 
executed  principally  under  his  direction. 

The  figures  35-50  are  taken  by  permission  from  the  Portfeuille  des 
Ponts  et  Chaussdes. 

Chapter  VI. — Villez  movable  dam  on  the  Seine. 

(79)  The  Villez  Dam  is  situated  on  the  Seine  145  kilometers  from 
Paris.  Figure  50  shows  the  general  arrangement  of  the  dam,  which 
consists  of  two  navigable  passes  and  a weir  having  a linear  opening 
of  201.25  meters,  together  with  two  locks.  The  total  length  of  the 
dam  is  223.15  meters. 

(80)  System  of  dosing. — The  dam  is  closed  by  a system  of  frames 
and  curtains  (Fig.  57).  Each  curtain  is  suspended  by  its  upper  bars 
from  a frame  over  two  adjacent  Poirde  frames  (fermettes).  This 
suspending  frame  is  completely  independent  of  the  fermettes,  being 
only  attached  to  them  by  pins  (Fig.  58). 

The  regulation  of  the  height  of  the  water  is  done  by  raising  or 
lowering  the  curtains,  the  flow  taking  place  underneath;  the  regu- 
lation, at  times  of  low  water,  maybe  made  without  moving  the  cur- 
tains, by  flash  boards  0.30  meter  high  arranged  above  the  curtains. 

(81)  Opening  the  dam. — The  process  of  completely  opening  the 

dam  is  as  follows:  The  curtain  frames  with  their  curtains  are 

transported  over  the  service  bridge  to  their  storehouse  on  the  bank ; 
the  flooring  of  this  bridge  and  the  rails  uniting  the  dam  frames  are 
taken  up ; and,  finally,  these  frames  are  lowered  one  after  another, 
beginning  with  the  one  in  each  pass  farthest  from  the  bank.  The 
time  taken  for  these  operations,  counting  from  the  carrying  away 


CIVIL  ENGINEERING,  ETC. 


GOT 


of  the  first  curtain,  is  about  22  hours,  corresponding  to  the  complete 
opening  of  one  linear  meter  in  11|  minutes.  When  the  freshet  sub- 
sides and  the  water  tends  to  fall  be- 
low the  normal  level,  the  inverse 
operations  are  made  and  the  dam 
is  closed. 

(82)  Description  of  the  dam. — The 
flooring  consists  of  a raised  portion, 
forming  the  upstream  sill,  united 
by  a curved  portion  with  a recess 
which  holds  the  lowered  frames; 
the  sill  is  4 meters  below  the  upper 
bay;  the  recess  protects  the  frames 
from  the  keels  of  the  passing  boats. 

The  great  pressure  supported  by 
the  frames  requires  their  bearings 
on  the  flooring  to  be  strong  and 
secure;  they  are  for  this  reason  at- 
tached to  iron  double  T bars  as 
long  as  the  width  of  the  recess,  and 
united  transversely  by  two  other 
double  T bars.  This  grating  is 
anchored,  as  well  as  built  into  the 
flooring.  In  constructing  the  floor- 
ing for  the  deep  passes  arrange- 
ments are  provided  for  setting  up 
a cofferdam  for  repairs.  These  ar- 
rangements consist  of  recesses  made 
in  the  piers  to  hold  joists,  so  as  to 
separate  adjacent  passes;  also  iron 
boxes  and  rings  anchored  in  the 
masonry  above  and  below  in  the 
flooring.  To  aid  in  pumping  out 
these  temporary  cofferdams,  a well 
is  sunk  in  each  floor.  These  sup- 
plementary constructions  were  of 
great  service  in  improving  the  sill 
of  the  dam  after  its  completion. 

(88)  The  frames. — The  frames 
are  planned  so  as  to  present  the 
minimum  of  obstruction  consistent 
with  strength.  The  upstream  up- 
rights of  the  frames  have  a small  T iron  on  their  face,  the  pro- 
jecting web  of  which  serves  as  a guide  to  the  curtain  bars  resting  on 
this  upright.  The  bracing  of  the  frames  is  calculated  on  the  sup- 
position that  the  pressure  of  the  water  is  distributed  over  the  whole 


60S 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


height  of  the  uprights,  instead  of  being  transmitted  only  at  the  top, 
as  in  the  case  of  needles. 

A bracket  placed  on  the  downstream  upright  serves  to  widen  the 
service  bridge  roadway  and  allows  two  tracks  to  be  laid,  the  rails 
serving  as  braces  between  the  frames,  and  replacing  the  catches  used 
in  the  older  frames. 

The  great  frames  are  moved  by  means  of  flatiron  bars,  each  in 
three  parts,  jointed  together,  and  having  a joint  at  each  extremity. 


Fig.  57.  Lowering  the  frames  at  Villez  Dam. 


(84)  Lowering  fhe  frames. — When  a frame  is  to  be  lowered  the 
joint  of  one  extremity  of  a bar  is  pinned  to  the  upper  cross  bar  of 
the  frame  and  the  other  extremity  made  fast  to  a car  movable  on  the 
track  on  the  service  bridge;  this  car  is  held  by  a chain  passed  around 
the  drum  of  a windlass,  the  latter  being  held  by  another  chain  made 
fast  to  the  next  pier  or  abutment  (Fig.  57).  To  lower  the  frame,  it 
is  only  necessary  to  push  the  car  forward  and  pay  out  the  windlass 
chain.  When  the  frame  is  lowered  the  flat  bar  fixed  to  the  car  is 


CIVIL  ENGINEERING,  ETC. 


609 


detached  and  pinned  to  the  side  of  the  cross  bar  of  the  following 
frame  still  standing;  the  operation  is  repeated,  and  while  the  second 
frame  is  lowered  the  Hat  jointed  bar  connecting  the  two  frames  folds 
together  forming  a V-  the  unequal  branches  coming  together  between 
the  two  frames,  without  forming  heaps  like  the  chains.  The  frames 
are  lifted  by  reversing  the  operation. 

(85)  Thetypeof  curtain  adopted  for  this  dam  (described  pp.  501-593) 
is  that  of  M.  Camerd.  The  dimensions  of  the  curtain  bars  for  the 
deepest  passes  are  1.09  meters  long,  0.058  meter  high,  and  the  thick- 
ness from  0.04  to  0.08  meter.  The  frame  supporting  the  curtain, 
which  also  holds  it  when  rolled  up,  is  an  iron  frame  (Figs.  58  and  59), 


DAM  AT  POSES. 


Fig.  58.— Windlass  for  hoisting  and  Fig.  59.— Mode  of  unshipping  and  trans- 

lowering  the  curtains.  porting  a curtain. 


whose  upper  bar  holds  the  hooks  for  the  suspending  chains,  and 
whose  uprights  are  terminated  by  forks  fitting  on  the  horizontal  pins 
with  heads  forming  part  of  the  dam  frame. 

By  means  of  these  pins  the  curtain  frame  may  be  set  up  directly 
over  the  uprights  of  two  successive  dam  frames  and  kept  in  this 
position  by  screws,  or  disengaged  and  turned  about  these  pins  and 
deposited  upon  the  curtain  car  (Fig.  59). 

The  curtain  frame  has  in  the  middle  two  guide  pulleys  which 
carry  the  curtain  chain,  and  a box  to  hold  the  slack  of  this  chain. 

(86)  The  curtain  is  rolled  or  unrolled  by  an  endless  chain  as  fol- 
lows: Each  line  of  the  endless  chain  passing  over  the  guide  pulleys 
forms  two  bights,  one  to  the  right  and  the  other  to  the  left  of  the 
curtain  frame  (Fig.  58);  the  one  passing  around  the  curtain  regulates 
the  amount  rolled  up.  To  operate  the  curtain,  the  two  lines  of 
the  chain  of  the  downstream  bight  pass  over  the  chain  pulleys  of 
the  windlass ; the  combined  motion  of  these  pulleys  produces  an 
elongation  or  contraction  of  the  other  bight. 

H.  Ex.  410 — vol  ill 39 


()10 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


(87)  The  windlass  for  handling  is  mounted  on  a car  rolling  on 
the  rails  of  the  foot  bridge  to  bring  it  in  front  of  the  curtain  to  be 
moved.  When  placed  it  is  clamped  to  one  rail  of  the  track  ; on  the 
other  side  a movable  buffer  on  the  upper  part  of  the  windlass  rests 
against  the  curtain  frame  and  resists  its  tendency  to  turn  in  the 
upstream  direction. 

The  windlass  carries  two  outside  chain  pulleys  (Fig.  58),  corre- 
sponding to  the  curtain-frame  guide  pulleys ; the  lines  of  chains  are 
put  upon  these  and  maintained  in  their  places  by  rotating  stops 
which  can  be  lifted  to  allow  the  chains  to  be  taken  off  or  put  on. 

The  pulleys  are  keyed  to  shafts  driven  by  the  windlass  gearing ; 
the  lower  pulley  may  be  engaged  or  disengaged.  When  engaged  it 
turns  in  an  opposite  direction  from  the  upper  pulley,  and  its  circum- 
ferential velocity  is  a fraction  of  that  of  the  other.  This  being  so, 
to  roll  up  the  curtain  the  lower  pulley  is  engaged,  and  the  upper 
pulley  exerts  an  effort  on  its  chain  while  the  lower  pulley  pays  out 
its  chain ; on  account  of  the  difference  of  the  velocities  of  the  two 
pulleys  a shortening  of  the  bight  passing  round  the  curtain  takes 
place,  and  the  curtain  rolls  up.  To  unroll  the  curtain,  the  lower 
pulley  is  disengaged,  its  chain  is  made  fast  by  a stop  on  the  guide 
pulley  of  the  curtain  frame,  the  upper  pulley  turns,  letting  go  the 
chain,  the  bight  lengthens,  and  the  curtain  unrolls. 

(88)  The  curtain  frame  is  shipped  on  a special  car  carrying  an 
inclined  plane  furnished  with  a windlass  and  chain  (Fig.  59).  This 
car  is  brought  in  front  of  the  curtain,  the  screws  fastening  the  cur- 
tain frame  to  the  dam  frame  are  removed,  so  as  to  allow  the  former 
to  turn  around  its  journals.  The  windlass  chain  is  hooked  to  the 
upper  bar  of  the  curtain  frame,  and  the  latter  turns  round  its  jour- 
nals until  it  rests  upon  the  inclined  plane;  then  by  the  continued 
action  of  the  windlass  it  is  hoisted  upon  the  car  by  moving  upon 
rollers  fixed  to  the  inclined  plane.  The  curtain  frame,  thus  com- 
pletely separated  from  the  dam  frames,  can  be  carried  off  on  the  car. 
It  is  replaced  by  the  reverse  process. 

The  project  for  the  Yillez  dam  was  prepared  under  the  direction  of 
M.  Lagrend,  chief  engineer,  by  M.  M.  Cheysson  and  Camerd,  engi- 
neers; the  latter  superintended  the  work  and  invented  the  system  of 
curtains. 

Chapter  VII. — Movable  fish  way  erected  at  Port-Mort  Dam 

on  the  Seine. 

(89)  A fish  swimming  up  a river,  meeting  a dam,  and  endeavoring 
to  ascend,  seeks  that  point  where  the  water  is  freshest;  this  is  in  the 
middle  of  the  pass — corresponding  to  the  main  channel  in  movable 
dams — and  not  under  the  shelter  of  the  fixed  parts;  so  that  fish  ways, 
if  we  wish  them  used,  should  be  placed  accordingly. 


CIVIL  ENGINEERING,  ETC. 


611 


Starting  from  these  principles  M.  Camerd  proposed,  in  1878,  to 
substitute  for  the  fixed  masonry  fish  ways  hitherto  constructed  near 
the  piers  or  abutments  of  movable  dams,  portable  fish  ways,  each 
formed  of  a long  trough  of  wood  or  sheet  iron  with  cross  parti- 
tions, resting  its  downstream  end  upon  a floater  and  its  upstream  end 
upon  the  upper  bar  of  the  curtain  dam  properly  lowered.  With  a 
construction  of  this  kind,  arranged  so  as  to  be  easily  shifted,  it  is 
possible  to  seek  in  the  dam  the  best  position  for  the  way  so  the  fish 
will  go  up  naturally,  and  the  route  which  they  choose  shall  not  be 
encumbered  by  any  fixed  obstruction. 


(90)  The  annexed  figure  indicates  the  arrangements  adopted  at 
Port-Mort.  The  dam  is  a curtain  dam,  like  that  at  Poses.  The 
wooden  trough  of  the  way  is  formed  "in  two  sections;  the  principal 
section  rests  on  the  floater,  and  is  hung  above  on  a shaft  arranged 
on  the  outer  faces  of  the  uprights  so  as  to  oscillate  as  the  lower  bay 
rises  and  falls.  The  second  section,  which  is  fixed,  is  placed  between 


612 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


two  uprights.  Its  extremity  opens  into  the  upper  bay,  and  it  joins 
the  other  section  upon  which  it  rests.  Its  length  has  been  deter- 
mined by  assuming  that  its  inclination  should  not  be  more  than  .020 
per  meter  when  the  dam  is  at  its  full  height.  The  length  of  the 
principal  section  is  therefore  10.15  meters;  its  width  beyond  the 
frames  is  1.4G  meters;  the  partitions,  0.43  meter  high  by  0.30  meter 
wide,  are  1.25  meters  apart. 

(01)  The  principal  section  rests  upon  a little  iron  bridge.  The 
downstream  floater  is  formed  by  two  little  covered  boats  arranged 
on  each  side  of  the  way  and  firmly  united. 

The  little  section  across  the  dam  frame  rests  above  on  the  upper 
bar  of  the  curtains  properly  lowered,  and  laterally  against  the  up- 
stream face  of  the  uprights  of  the  dam,  secured  by  angle  irons  fixed 
to  its  exterior  sides.  Below,  it  is  boxed  in  by  two  cheeks  arranged 
at  the  end  of  the  principal  sections,  and  rests  on  a cylindrical  sur- 
face, so  as  to  allow  oscillations.  The  portion  situated  at  the  entrance 
of  the  trough  in  the  upper  bay  is  movable  around  an  axis  placed  at 
its  base.  This  allows  the  regulation  of  water  flowing  down  the  way 
according  to  the  level  of  the  lower  bay. 

(92)  Erection. — The  way  is  set  up  between  two  frames.  To  lower 
it  it  is  sufficient  to  lower  the  upper  bars  of  the  two  curtains  on  which 
it  rests  by  lengthening  their  suspending  chains.  We  thus  obtain 
sufficient  space  above.  The  portion  of  this  space  not  filled  by  the 
way,  is  closed  on  each  side  by  two  little  hand  sluices.  The  chains 
holding  the  suspension  axle  of  the  way  are  hooked  in  the  uprights 
of  the  dam  and  the  axle  is  made  fast  by  other  chains  attached  to  the 
frame  shaft.  The  fish  way  is  brought  into  place  with  its  upper  ex- 
tremity resting  on  a pontoon,  while  its  lower  extremity  rests  on  the 
floaters.  By  attaching  then  the  upper  end  of  the  way  to  the  top  of 
the  service  bridge  the  bearings  placed  under  the  beams  are  put  upon 
the  axle,  and  the  floater  is  held  by  guys  from  the  neighboring  piers. 
The  curved  piece  connecting  the  two  portions  of  the  troughs  is  put 
up  across  the  dam  frames.  To  remove  the  way  the  inverse  opera- 
tions are  performed. 

The  movable  fish  way  for  this  dam  was  planned  and  executed 
under  the  direction  of  M.  Camerd  by  M.  Clerc. 

Chapter  VIII.— Torcy-Neuf  Reservoir  for  feeding  the  Cen- 
tral Canal. 

(93)  The  great  improvements  for  deepening  the  Central  Canal,  re- 
quired the  establishment  of  a new  storage  dam  near  Creusot.  The 
new  reservoir  received  the  name  of  Torcy-Neuf  to  distinguish  it  from 
another  called  Torcy. 

Torcy-Neuf  is  5 kilometers  northwest  from  the  summit  level  of 
the  Central  Canal. 


CIVIL  ENGINEERING,  1 TC. 


613 


The  reservoir  has  a surface  of  166  hectares,  a perimeter  of  15  kilo- 
meters, a height  of  14.50  meters;  it  contains  8,767,000  cubic  meters, 
and  doubles  the  amount  of  water  heretofore  available  at  this  level. 

A waste  weir  12  meters  long  is  at  the  left  end  of  the  dike.  The 
supply  conduits  start  from  a tower  which  is  built  in  the  reservoir 
at  the  foot  of  the  dike,  and  which  allows  the  waste  water  to  flow 
over  the  top. 

(94)  The  dike,  well  rooted  at  both  ends  in  the  side  of  a hill,  con- 
sists of  a great  filling  of  sand  and  clay  (64  per  cent  of  sand  to  34 


of  clay)  436.70  meters  long,  5.50  meters  wide  at  the  top,  and  52.90 
meters,  at  the  base  ; its  maximum  height  is  16.30  meters,  and  its  vol- 
ume 129,000  cubic  meters. 

The  slope  toward  the  water  (Fig.  62)  is  protected  by  a series  of 
masonry  pitcliings  1.50  meters  high,  inclined  45  degrees,  and  sepa- 
rated by  berms  0.90  meter  wide,  two  intermediate  oues  being  2 meters 
wide. 


614 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


The  exterior  slope,  without  revetment,  is  planted  with  acacias 
fora  distance  of  5 meters  in  height.  The  slope  is  2.73  base  to  2 of 
height. 

The  upper  platform  of  the  dike  is  1.80  meters  above  the  water 
level;  it  is  of  masonry,  like  the  slope  toward  the  water,  and  sur- 
mounted by  a parapet  1.20  meters,  to  stop  the  waves.  The  foot  of 
the  slope  rests  on  a revetment  wall  1.50  meters  thick,  built  in  a 
distance  of  1 meter  into  the  solid  rock  (red  sandstone)  for  the 
whole  length  of  the  dike.  The  maximum  height  of  this  wall  is  7 
meters. 

The  dike,  below  the  revetment  and  the  platform,  rests  on  bare 
rock.  To  increase  the  tightness  at  the  base  there  were  three  layers 
of  puddled  clay  laid  down  within  the  reservoir  parallel  to  the  axis 
of  the  dike  and  penetrating  1 meter  into  the  rock  foundation. 

The  earth  of  the  dike  was  vigorously  rolled  in  successive  layei*s, 
after  adding  water  and  powdered  lime  according  to  their  degree  of 
dampness;  the  layers  being  compressed  from  0.10  to  0.075  meter  after 
the  operation.  Corrugated  rollers  drawn  by  horses  and  weighing 
750  kilograms,  and  also  steam  rollers  weighing  5,000  kilograms  were 
used.  A horse-roller  compressed  80  cubic  meters  per  day,  measured 
after  compression,  while  a steam  roller  compressed  500  meters.  The 
cost,  including  leveling,  watering,  addition  of  lime,  rolling,  etc.,  was 
0.23  franc  per  cubic  meter. 

That  part  of  the  dike  under  the  outside  slope  was  rammed  in  lay- 
ers of  0.20  meter  thick,  reduced  to  0.15  meter  after  rolling;  it  rests 
on  a natural  bed  carefully  prepared. 

(95)  7 he  (fate  tower. — The  water,  instead  of  being  conveyed  in 
mains  or  culverts  through  the  dike,  is  let  into  a tower  built  in  the 
reservoir  at  the  foot  of  the  dike.  It  serves  to  discharge  the  waste 
water  and  dispenses  with  the  waste  weir;  this  weir  has  been  retained 
through  fear  lest  the  large  amount  of  water  flowing  through  the 
tower  should  undermine  or  dislocate  the  masonry.  These  appre- 
hensions proved  groundless.  The  experiment  of  passing  the  waste 
water  through  the  tower,  combined  with  the  gate  closing  the  tail- 
race,  has  been  perfectly  successful. 

The  gate  tower  is  square  on  the  outside  and  has  in  the  interior  a 
well  1.50  meters  in  diameter  through  which  the  mouthpieces  pass. 
This  well  opens  below  into  the  tail  race. 

The  coping  of  the  tower  is  on  the  same  level  as  that  of  the  dike, 
that  is,  16.30  meters  above  the  bottom  of  the  lowest  mouthpiece. 
It  has  a platform  3.50  meters  square,  on  which  is  placed  the  appara- 
tus for  moving  the  gates.  The  faces  of  the  tower  have  a batter  of 
one-twentieth. 

The  well  terminates  in  a cylindrical  chamber  2 meters  in  diameter 
and  2 meters  deep,  kept  constantly  full  of  water  to  break  the  destruc- 


CIVIL  ENGINEERING,  ETC. 


015 


tive  shock  of  the  water  upon  the  masonry.  Founded  on  red  sand- 
stone, the  tower  exerts  a pressure  of  3.58  kilograms  per  square  centi- 
meter. 


(96)  There  are  three  mouthpieces,  situated  vertically  over  each 
other  at  a distance  of  4.80  meters  apart.  The  orifices  are  0.80  by 
0.40  meter  and  are  closed  by  special  cylindrical  valves.  The  middle 


616 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


and  upper  mouthpieces  are  simple  ducts  of  rectangular  section 
opened  in  the  walls  of  the  tower;  their  bottoms  are  curved  so  as  to 
intersect  the  walls  at  an  angle  of  45  degrees,  so  that  the  stream  at 
the  moment  of  opening  shall  strike  the  masonry  obliquely. 

The  water  is  let  into  the  tower  by  four  openings,  each  2.20  meters 
long,  made  at  the  top  of  its  four  faces;  the  sills  of  these  openings  are 
0.40  meter  below  the  standard  level.  Each  of  them  is  surmounted 
by  an  oaken  gate  kept  in  its  place  by  (J  irons  fastened  against  the 
sides  of  the  openings.  These  gates  are  taken  off  in  case  of  a freshet. 

The  tower  is  accessible  from  the  dike  by  an  iron  foot  bridge.  The 
ribbed  plate  flooring,  21.40  meters  long,  1.14  meters  wide,  is  sup- 
ported on  two  arches  of  18.20  meters  chord  and  2.50  meters  rise. 
The  new  system  of  valve  towers  has  the  advantage  of  economy, 
combined  with  greater  security  and  stability  for  the  dike,  as  well  as 
affording  greater  facilities  for  repairs. 

(97)  The  passage  of  the  water  mains  through  a mass  of  masonry 
in  an  earthen  dike  destroys  the  homogeneity  of  the  latter;  on  both 
sides  of  this  mass  the  earth  has  to  be  hand-rammed,  and  consequently 
badly  done,  no  matter  how  much  care  is  taken.  The  settlement  of 
this  earth  leaves  spaces  which  may  cause  filtrations  and  become 
sources  of  real  danger. 

With  the  tower,  the  dike  is  only  cut  at  its  base;  the  hand-ramming 
is  reduced  to  a minimum  ; as  soon  as  the  top  of  the  waste  culvert  is 
reached,  all  the  ramming  is  done  with  rollers,  and  consequently 
much  better.  A notable  economy  results  from  dispensing  with  the 
heavy  masses  of  masonry  through  which  ordinarily  the  mains  run, 
from  the  omission  of  the  waste  weir  with  its  tail  race,  and  from 
rolling  by  steam  and  horse  power  instead  of  ramming  by  hand. 

The  sluices  are  very  difficult  of  access  in  the  long  culverts  ordi- 
narily used,  and  are  consequently  rarely  repaired.  With  the  tower, 
on  the  contrary,  when  the  mouth  of  a main  has  been  stopped  by  a 
wooden  plug,  placed  within  the  tower  in  a chamber  arranged  for  this 
purpose,  a diver  can  easily  take  down  the  valves  and  valve  rods,  and 
replace  them  after  they  have  been  repaired  in  the  shop. 

The  long  culvert  under  the  dike  can  be  easily  inspected  and  re- 
paired. The  guard  sluice  being  raised,  one  is  not  entirely  cut  off  from 
the  upper  end  ; light  and  air  come  in  from  the  tower. 

(98)  Sluices. — Rectangular  sluices  have  the  great  inconvenience 
of  moving  with  very  considerable  friction  for  great  heads  of  water  ; 
use  has  to  be  made  of  powerful  and  costly  jacks,  whose  friction  in- 
creases the  effort  to  be  made ; they  have  to  be  fastened  by  heavy 
irons  to  solid  pieces  of  masonry,  that  they  may  not  give  way. 

At  Torcy-Neuf  the  endeavor  has  been  to  diminish  the  friction  as 
much  as  possible  and  consequently  to  employ  simpler  moving  appa- 
ratus. 


CIVIL  ENGINEERING,  ETC. 


617 


The  sluice  (Figs.  G3  and  04)  is  not  plane  but  cylindrical,  and  firmly 
attached  to  a rigid  horizontal  concentric  shaft ; it  has  no  opening. 
It  turns  at  a short  distance  from  its  seat,  which  is  cylindrical  and 
concentric,  without  resting  upon  it.  It  includes  a movable  frame 
which  it  carries  with  it  in  its  motion,  but  the  latter  is  not  attached 
to  the  shaft.  The  pressure  of  the  water  on  this  frame  is  exerted  only 
at  its  edges  ; it  rests  and  rubs  only  against  the  valve  seat.  The  joint 


Fios.  63,  64,  65.— Torcy  Neuf  reservoir.  Section,  elevation,  and  details  of  the  sluice. 


between  the  frame  and  sluice  is  packed  with  a rubber  ring,  which 
does  not  sensibly  interfere  with  the  independence  of  the  frame;  this 
ring  is  inclosed  in  a slot  and  protected  from  shocks. 

Comparing  this  with  the  ordinary  flat  sluice,  the  theoretical  friction 
is  reduced  92  per  cent.  This  system,  which  gives  entire  satisfaction, 
is  due  to  M.  Eugene  Resal.  The  three  sluices  are  moved  by  jacks 
placed  on  a single  post  in  the  middle  of  the  platform  of  the  tower ; 


618 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


the  motion  is  transmitted  to  the  rods  by  endless  chains  and  horizon- 
tal axles. 

(90)  Guard  sluice. — The  guard  sluice,  at  the  bottom  of  the  tower, 
to  close  the  waste  culvert  is  upon  the  same  principle.  It  was  devised 
by  M.  Hirsch,  chief  engineer.  It  is  principally  of  iron,  1.80  meters 
high  and  1.10  meters  wide  ; it  consists  of  a strong  plate  iron  wagon- 
ette with  two  pairs  of  wheels,  rolling  on  vertical  rails  set  into  the 
walls  of  the  masonry  well  (Figs.  06,  07,  68,  and  09).  The  wagonette 
rises  without  resting  against  a cast-iron  frame  fixed  in  front  of  the 


Fig.  68. 


Fig.  69. 

Figs.  66,  67,  68,  69.— Torey  Neuf  reservoir.  Elevation,  vertical  section,  and  horizontal  section  of  the 

guard  gate,  with  details. 


culvert.  The  contact  takes  place  along  a slightly  inclined  plane  by 
a border  formed  of  jointed  bronze  rules  independent  of  the  sluice, 
but  carried  along  with  it  in  its  motion.  Like  the  other  sluice,  it  is 
packed  by  rubber  between  the  jointed  rules  and  the  wagonette ; the 
faces  of  contact  of  the  rules  and  the  rubber  are  galvanized.  The 
jack  moving  the  suspending  rod  is  placed  on  the  platform  of  the 
tower. 


CIVIL  ENGINEERING,  ETC. 


619 


The  head  of  water  on  the  center  of  t lie  guard  sluice  is  13.60  meters 
while  the  pressure  on  a simple  plain  sluice  having  a surface  of  2 
square  meters  would  be  about  27,000  kilograms;  the  rules  are  only 
pressed  against  the  seat  with  a force  of  3,000  kilograms.  Admitting 
a coefficient  of  40  per  cent  for  friction,  the  weight  of  the  sluice  being 
1,000  kilograms,  the  effort  to  raise  the  sluice  does  not  exceed  2,200 
kilograms,  which  is  easily  managed  by  a jack  with  a -theoretical 
power  of  750. 

This  sluice  was  set  up  in  1S88  and  works  perfectly.  It  affords  the 
means,  as  it  is  raised  more  or  less,  of  keeping  the  water  in  the  tower 
at  such  a given  constant  height  as  may  be  found  most  advantageous. 
We  may  thus  diminish  at  will  the  height  of  fall  of  the  water  into 
the  tower. 

(100)  Cost. — The  total  cost  of  the  work  was  2,233,183.84  francs. 
The  cost  of  the  dike,  tower,  and  waste  weir  together  was  585,896.53 
francs.  The  rest  was  spent  for  land,  buildings,  and  the  removal  and 
reestablishment  of  the  roads  and  railroad  passing  through  the  loca- 
tion. 

The  project  was  prepared  by  MM.  Desmur,  engineer,  and  Fontaine, 
chief  engineer. 


Chapter  IX. — New  high  lift  locks  on  the  Central  Canal. 

(101)  The  French  Government  has  just  completed  a number  of 
high  lift  locks  on  the  central  canal  to  replace  old  ones  of  2.60  meters 
lift.  The  new  locks  have  a lift  of  5.20  meters  with  chamber  wall 
8.20  meters  high.  The  flooring  is  0.25  meter  below  the  head  miter 
sill  and  2.85  meters  below  the  normal  level.  The  cylindrical  supply 
sluice  (Fig.  75)  is  placed  at  the  bottom  of  each  upstream  quoin  un- 
der a full  centered  arch  of  2.30  meters  span  and  2.55  meters  height. 
Two  small  recesses  serve  to  support  a little  joist  dam  allowing  the 
sluice  chamber  to  be  emptied  and  the  sluice  inspected  and  repaired 
without  stopping  the  traffic.  A grating  is  ordinarily  placed  in  these 
recesses  to  stop  floating  bodies. 

(102)  The  lift  wall  is  5.20  meters  high  and  1.60  meters  thick  with 
the  downstream  face  curved.  The  cylindrical  sluice  pits,  1.40  me- 
ters in  diameter,  are  sunk  in  each  chamber  wall  to  a depth  of  4.95 
meters.  From  the  bottom  of  these  pits  on  a level  with  the  tail  miter 
sill,  the  full  centered  culvert  begins,  for  filling  and  emptying  the 
chamber.  It  extends  lengthwise  through  the  entire  chamber  and 
discharges  into  it  by  four  rectangular  openings  equally  distributed, 
from  0.60  to  0.80  meter  wide  by  0.80  to  1 meter  high.  The  largest 
admits  the  passage  of  a man  for  inspection  or  repairs.  The  chord 
of  the  invert  is  2.60  meters  below  the  normal  level,  2 meters,  of  the 
tail  bay.  (Fig.  70.) 


620 


UNIVERSAL  EXPOSITION  OE  1889  AT  PARIS. 


Under  the  flooring,  two  files  of  drains  begin  10  meters  from  the 
lift  wall,  emptying  into  the  riprap  of  the  tail  bay.  All  upward  pres- 
sure is  thus  avoided  besides  facilitating  the  foundation  constructions. 


Each  chamber  wall  is3.G0  meters  thick  at  the  base,  and  1.20  me- 
ters at  the  top;  it  is  8.20  meters  high.  Two  life  ladders  formed  of 
iron  bars  are  placed  in  little  recesses  in  the  walls. 


CIVIL  ENGINEERING,  ETC. 


621 


To  resist  the  thrust  oil  the  tail  gates,  the  tail  walls  are  4.34  meters 
at  the  top  and  G meters  at  the  base,  terminated  by  wing  walls  hav- 
ing a batter  of  one-twentieth  (Fig.  74). 

Two  recesses  allow  a cofferdam  to  be  set  up  to  separate  the  lock 
chamber  from  the  tail  bay. 

A short  distance  upstream  from  the  tail  quoins,  the  lateral  culvert 
in  each  chamber  wall  rises  and  empties  into  a large  pit  2.30  meters 
square  and  6.25  meters  high,  in  which  the  cylindrical  emptying  valve 
is  placed  (Fig.  76).  This  pit,  and  the  lock  chamber  form  two  reser- 
voirs communicating  by  four  rectangular  orifices  equally  for  filling 
and  emptying.  The  water  reaches  the  pit  and  escapes  at  the  bottom 
under  the  boats  without  producing  any  current  in  the  chamber.  The 
valve  seat  is  0.65  meter  below  the  level  of  the  tail  bay,  so  as  not  to 
make  a siphon  of  the  discharging  culvert,  and  also  to  allow  the  in- 
spection of  the  sluice  by  a slight  lowering  of  the  tail  bay. 


Figs.  75  and  76.  — Half  cross  sections  through  the  axes  of  the  upstream  and  downstream  pits. 


This  sluice  opens  a pit  1.40  meters  in  diameter  and  1.95  meters 
high,  at  the  bottom  of  which,  at  the  level  of  the  tail  miter  sill,  the 
emptying  culvert  begins.  This  latter  having  a great  section,  1 me- 
ter wide  and  from  1.60  to  2 meters  high,  makes  a circuit  of  the  hol- 
low quoin  so  as  to  empty  into  the  tail  bay  at  right  angles  to  the  axis 
of  the  lock,  thffs  avoiding  the  introduction  of  the  water  with  great 
velocity  into  the  tail  bay,  and  consequent  erosion.  One  of  these  high 
lift  locks  has  a bridge  erected  on  the  tail  walls;  the  roadway  being 
1.30  meters  below  the  coping,  it  is  6.80  meters  span  and  covers,  be- 
side the  boat  passages,  two  staircases  each  0.80  meter  wide. 

(103)  Description  of  the  cylindrical  sluices  (Fig.  77). — The  lock 
has  four  cylindrical  cast-iron  sluices  of  equal  size,  two  for  filling, 
and  two  for  emptying. 

Each  sluice  consists  of  fixed  and  movable  parts.  The  fixed  parts 
consist  of  a seat  1.40  meters  in  diameter,  built  in  and  fastened  to  the 
masonry,  and  carrying  three  uprights  in  the  form  of  flanges  united 
"by  an  upper  crown;  a hollow  cylinder  fixed  upon  the  crown  receiv- 


G22 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


ing  the  sluice  when  it  is  raised;  a cover  bolted  to  this  cylinder  and 
surmounted  by  a pipe  for  the  passage  of  the  lilting  rod  and  the 
escape  of  air.  The  seat  is  placed  horizontal  and  maintained  so  by 
means  of  three  regulating  screws  embedded  afterwards  in  cement. 

The  movable  part  is  a cast-iron  crown  0.4G7  meter  in  height,  and 
1.42  meters  in  interior  diameter  raised  by  a jack.  It  slides  on  a fixed 
part  and  opens  or  closes  the  space  between  the  seat  and  the  upper 
cylinder.  The  vertical  pressure  of  the  water  is  supported  by  the 
cover.  The  movable  portion  only  is  exposed  to  lateral  pressures 
which  are  in  equilibrium.  The  only  weight  to  be  raised  is  the 


Fig.  77.— Cross  section  of  Fontaine's  cylindrical  sluice;  the  sluice  closed. 


weight  of  the  sluice,  which  is  about  370  kilograms.  The  distance 
raised  is  0.385  meter;  the  time  of  raising  twelve  or  thirteen  seconds 
and  the  effort  only  7 kilograms.  The  downstream  sluices  work  un- 
der a head  of  5.20  meters  as  easily  as  the  upstream  ones  under  the 
head  of  2.  GO  meters. 

The  closed  sluice  rests  on  a little  rubber  ring,  fastened  into  a slot 
in  the  seat.  The  upper  joint  is  made  tight  by  a leather  band,  kept 
in  place  by  the  pressure  of  the  water.  This  sluice,  which  has  been 
in  use  for  the  last  six  years,  has  worked  perfectly.  It  has  the  follow- 
ing advantages : 


CIVIL  ENGINEERING,  ETC. 


623 

First.  There  are  no  resistances  except  the  weight  and  friction  of 
the  water  on  the  iron,  without  any  pressure  of  the  water. 


raising  the  sluice  a height  /i=  . 


Figs.  78  and  79.— Lock  on  the  Central  Canal.  Upstream  elevation  and  section  of  the  lower  gates  of  the  canal  lock. 


624 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


Third.  The  head  is  greater  than  upon  an  equal  orifice  made  in  a 
vertical  plane.  This  sluice  has  been  adopted  elsewhere  for  Paris 
and  for  sea  locks.  It  solves  the  problem  of  liigh-lift  locks  with 
saving  basins.  For  great  reservoirs,  a single  cylindrical  sluice  of 
small  diameter  will  advantageously  replace  the  usual,  complicated 
and  expensive  systems. 

The  use  of  cylindrical  sluices  enables  all  others  to  be  dispensed 
with,  which  is  an  advantage  with  respect  to  tightness  and  repairs. 
The  hand  rails,  for  this  reason,  can  be  placed  on  the  upstream  side 
of  the  foot  bridge,  and  thus  sheltered  from  the  shocks  of  passing 
boats  when  the  leaf  is  opened. 

(104)  Gates. — The  head  gates  consist  of  two  leaves  of  galvanized 
plate  iron.  The  tail  gates  are  9.25  meters  high,  including  the  hand 
rail ; they  consist  of  two  leaves  of  galvanized  plate  iron  and  steel. 
Each  has  a frame  strengthened  by  eight  horizontal  beams  so  spaced 
as  to  support  about  the  same  load,  and  by  ten  uprights  united  by  the 
first  set.  These  pieces  consist  of  a web  and  four  angle  irons  of  mild 
steel.  By  the  use  of  this  metal  the  weight  of  the  frame  is  reduced, 
making  an  economy  of  construction,  and  facilitating  the  setting  up 
and  the  working. 

The  heel  and  miter  posts,  as  well  as  the  uprights,  are  strengthened 
by  three  wide  iron  bands  on  their  downstream  faces,  to  give  them 
more  stiffness.  The  skin  is  formed  by  eighteen  iron  plates  0.007  me- 
ter thick,  built  in  at  the  edges,  curved  so  as  to  have  a flexure  of  0.070 
meter,  and  riveted  to  the  upstream  face  of  the  steel  frame.  They 
show  no  change  of  form  under  pressure. 

The  pressure  of  the  leaf  against  the  heel  post  at  the  bottom  is 
spread  over  seven  iron  disks  upon  friction  plates;  these  last,  fur- 
nished with  three  adjusting  screws,  are  arranged  so  that  all  bear 
and  work. 

The  collar,  fixed  to  the  anchor  straps  by  two  strong  screws  and 
nuts,  has  a joint  besides.  It  can  move  horizontally  in  all  directions 
and  give  the  axis  of  rotation  an  exact  vertical  position. 

Each  leaf  is  furnished  with  a gridiron  valve  formed  of  two  hollow 
cast-iron  cylinders  united  by  flanges,  to  be  used  in  the  case — which 
may  never  happen — when  the  water  is  so  low  as  to  uncover  the  sills 
of  the  cylindrical  sluices. 

All  the  gates  are  moved  easily,  even  by  children,  by  means  of 
little  simple  and  convenient  windlasses. 

(105)  Time  of  lockage. — The  lock,  containing  1,200  cubic  meters, 
is  filled  in  3 minutes  10  seconds  and  emptied  in  3 minutes  15  seconds; 
the  time  for  lockage,  14  minutes,  being  thus  distributed: 

Min.  Sec. 


Entrance  of  the  boat 4 10 

Closing  the  gates 0 40 

Filling  the  chamber 3 10 

Opening  the  gates 0 40 

Exit  of  the  boat 5 20 


CIVIL  ENGINEERING,  ETC.  625 

(106)  Cost. — The  cost  of  the  lock  was  120,000  francs,  made  up  as 


follows: 

Francs. 

Earthwork 8,000 

Masonry  work 96, 000 

Lock  gates 11, 100 

Cylindrical  sluices 3, 400 

Gratings  and  windlasses 1 , 500 


Total 120, 000 


The  new  lock  appears  to  be  very  satisfactory,  and  promises  to  be- 
come the  type  to  be  adopted  in  future.  The  rapidity  of  lockage 
without  injury  to  the  boats  from  the  motion  of  the  water,  and  the 
ease  of  operating  all  the  appliances,  are  thoroughly  appreciated. 

The  group  of  locks,  of  which  this  was  one,  was  designed  and  exe- 
cuted under  the  direction  of  M.  Fontaine,  chief  engineer,  by  Messrs. 
Resal,  Moraillon,  and  Variot,  assistant  engineers. 

Chapter  X. — Cable  towage  for  boats  on  canals  and  rivers. 

(107)  The  principal  difficulties  in  cable  towage  arise  from  the  fol- 
lowing circumstances: 

First.  That  owing  to  the  obliquity  of  the  towrope,  the  irregularity 
of  its  motion,  and  the  displacement  of  the  joint  between  the  rope  and 
the  cable,  the  cable  can  not  have  a steady  motion. 

Second.  Whenever  the  towrope  passes  over  the  groove  of  a guide 
pulley  it  is  caught  there.  It  must  pass  the  pulley  without  dragging 
the  cable,  which  is  a difficult  matter,  especially  in  going  around 
concave  curves. 

Third.  The  joint  between  the  towrope  and  the  cable  should  be 
such  that  the  former  can  not  be  twisted  upon  the  latter  by  the 
torsion  of  the  cable,  otherwise  the  towrope  will  be  wound  upon  it, 
besides  being  very  difficult  to  detach  from  it. 

Fourth.  The  towrope  must  be  easily  detached  from  the  cable  at 
any  instant — an  operation  of  some  difficulty,  as  it  is  done  by  a cord 
60,  80,  or  150  meters  long,  which  forms  knots  by  being  dragged  on 
the  ground  or  through  the  water. 

Fifth.  Uncoupling  should  be  progressive,  although  we  couple 
suddenly  to  a cable  in  motion. 

(108)  System  adopted. — The  system  of  cable  towage  introduced  by 
M.  Maurice  Levy  solves  all  these  difficulties  as  follows: — 

The  first  condition  of  success  was,  according  to  the  author,  to  avoid 
all  irregular  motions  of  the  cable.  For  this  purpose,  instead  of  de- 
termining the  weight  and  tension  of  the  cable  according  to  the  usual 
rules  governing  telodynamic  transmission,  he  determines  them  by 
the  double  condition  of  maintaining  the  oscillations  of  the  cable, 
H.  Ex.  410 — vol  ill 40 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


626 

whether  horizontal  ov  vertical,  within  certain  prescribed  limits, 
which  can  he  made  as  small  as  may  be  desired.  This  requires  that 
the  cable  should  be  heavy  (about  3 kilograms  per  meter),  and  that 
it  should  be  set  up  with  an  initial  tension  incomparably  greater 


than  that  usually  adopted  in  telodynamic  cables.  This  tension,  as 
well  as  the  weight  of  the  cable,  depends  on  the  length  of  circuit  and 
the  speed  required  for  the  boats. 


This  figure  is  taken  by  permission  from  La  Nature. 


627 


CIVIL  ENGINEERING,  ETC. 

The  vertical  supporting  pulleys  are  0.80  meter  in  diameter,  and 
have  a depth  of  groove  of  0.20  meter.  A roller  on  the  top  of  the 
pulley  prevents  the  cable  from  leaving  it,  but  the  towrope  attachment 
would  catch  between  the  pulley  and  the  guide  roller.  To  obviate 
this  openings  are  made  on  the  water  side  of  the  pulley  grooves,  con- 
sisting of  notches  extending  the  whole  width  of  the  groove  and  hav- 
ing their  edges  curved  in  the  form  of  the  involute  of  a circle  (Fig. 
80). 

The  towrope  joint,  or  coupling,  remains  in  the  groove  until  it  is 
caught  by  the  first  notch,  which  it  follows;  then,  on  account  of  the 
obliquity  of  the  towrope,  it  descends  along  one  edge,  is  carried  up  on 
the  other,  and  passes  off. 

(109)  The  passage  around  convex  bends  in  the  banks  presents  no 
difficulty;  it  is  accomplished  with  the  aid  of  a horizontal  pulley,  or 
rather  one  slightly  inclined  in  the  direction  of  the  two  sides  of  the 
endless  cable.  Two  types  of  pulleys  are  adopted:  one  1.40  meters 
and  the  other  2 meters  in  diameter  at  the  bottom  of  the  grooves,  with 
0. 10  meter  depth  of  groove.  The  first,  for  curves  from  200  to  300 
meters  radius,  and  the  second  for  those  of  smaller  radii.  These 
pulleys  have  no  need  of  notches,  as  the  cable,  with  its  towrope  coup- 
ling, only  passes  on  the  water  side  and  thus  escapes.  On  account  of 
the  great  tension  of  the  cable  there  is  no  danger  that  the  towrope  will 
pull  it  off. 

(110)  The  passage  around  concave  angles  is,  on  the  contrary,  an 
extremely  delicate  problem.  In  that  case,  the  cable  passing  round 
the  pulley  on  the  land  side,  the  towrope  joint  can  not  clear  itself 
unless  we  adopt  very  special  and  precise  arrangements. 

The  following  method  was  adopted  (Figs.  81  and  82): 

In  the  elevation,  the  plane  of  the  lower  pulley  is  supposed  to  be  re- 
volved to  coincide  with  that  of  the  upper  one. 

Two  vei’tical  pulleys  are  taken,  having  a common  tangent,  to  the 
bottom  of  their  respective  grooves,  one  of  the  pulleys  being  in  the 
plane  of  the  part  coming  on,  and  the  other  in  that  of  the  part  going 
off.  The  cable  rolls  upon  the  first  (which  we  may  suppose  to  be  the 
upper  one)  and  descends  vertically  along  the  common  tangent,  and 
then  passes  on  to  the  second. 

This  solution  permits  any  change  of  direction  whatever  by  the 
aid  of  two  vertical  pulleys,  and  consequently  it  suffices  to  notch  these 
pulleys  like  the  supporting  pulleys  to  let  the  towrope  coupling  es- 
cape. But  it  subjects  the  cable  to  two  consecutive  bends  at  right 
angles.  In  order  to  save  the  cable  from  wear,  large  2-meter  pulleys 
are  used,  and  on  account  of  tlieir  great  dimensions  the  number  of 
the  notches  is  increased. 

The  expense  of  such  pulleys  with  tlieir  supports  would  be  con- 
siderable if  they  had  to  be  used  wherever  there  is  a concave  angle, 


628 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


and  this  arrangement  is  only  suitable  for  curves  with  exceptionally 
short  radii,  or  at  the  entrance  of  tunnels,  Avhere  it  maybe  convenient 
to  suddenly  change  the  direction.  For  the  usual  deviations  a large 
pulley  is  used  of  the  type  of  1.40  or  2 meters,  furnished  with  notches 
on  the  upper  face  (Fig.  83).  This  solution  is  derived  from  that  of 
the  two  vertical  pulleys. 


Figs.  81  and  82.— Cable  towage.  Elevation  and  plan  of  a double  pulley  for  a concave  angle.  The 
cable  comes  on  to  the  upper  pulley  and  passes  to  the  lower. 

The  principle  of  the  two  pulleys  is  very  elastic.  We  may,  for 
instance,  take  both  pulleys  inclined,  or  one  vertical  and  the  other 
inclined.  Then  we  may  arrange  so  that  the  first  shall  he  an  ordinary 
pulley  0.60  meter,  and  there  remains  only  one  large  pulley.  But  the 
inclination  of  the  latter,  its  direction  relatively  to  that  of  the  cable 


CIVIL  ENGINEERING,  ETC. 


629 


as  it  comes  on  and  goes  off,  and  the  length  and  width  of  the  notches, 
should  he  determined  with  the  most  perfect  precision  by  certain 
rules  which  have  been  established  by  theory  and  experiment. 

(Ill)  Method  of  attaching  the  boats  to  the  cable. — The  towrope  can 
not  be  made  fast  directly  to  the  cable,  because  the  latter  being  sub- 
jected to  constant  twisting  motions 
would  cause  the  former  to  twist  around 
it,  thereby  losing  considerable  of  its 
length,  and  rendering  its  detachment 
impossible  during  the  journey.  This 
detachment  should  be  capable  of  being 
instantly  done  in  case  of  an  accident,  or 
when  the  boat  is  to  be  stopped.  For 
this  reason  cable-road  grips  are  inap- 
plicable ; hence  pairs  of  rings  are  placed 
at  intervals  on  the  cable  (Fig.  80).  One 
ring  serves  as  a fixed  axis  of  rotation  to 
the  other  ring  which  is  movable  about  fig.  as. -single  puUey  for  concave 

the  cable.  The  latter  ring  has  two  bear-  angles, 

ings  around  which  the  U -shaped  shackle  turns.  This  shackle  may 
therefore  have  two  rotations,  one  around  the  cable  and  the  other 
around  an  axis  perpendicular  to  it. 


Figs.  84  and  85.—  Elevation  and  section  of  the  hooking  on  and  casting  off  grip. 


The  grip  attached  to  the  towrope  consists  of  a hollow  cylinder  c 
c c c,  in  which  the  piston  G G G moves;  the  piston  rod  p q passing 
through  the  bottom  of  the  cylinder;  one  end  of  a spiral  spring  sur- 
rounding the  rod  p q rests  against  the  bottom  of  the  cylinder  G G, 
and  the  other  against  the  piston. 


630 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


A frame  P Q is  placed  in  a diametral  plane  of  the  cylinder  and 
attached  to  it;  it  carries  a finger,  D,  movable  around  an  axle;  the  end 
of  the  finger  fits  into  a cylindrical  cavity  in  the  piston  G G.  If  D is 
put  in  the  cavity  it  is  caught  there.  If  the  rod  p is  pulled  the  piston 
follows  it,  compressing  the  spring;  the  finger  D then  becomes  free  to 
turn  on  its  axis. 

The  end  of  the  towrope  on  the  boat  is  permanently  attached  by  a 
ring  to  P.  One  extremity  of  the  grip  cord  is  on  the  boat  and  the 
other  permanently  attached  to  p (Fig.  86). 

The  cord  is  for  releasing  the  finger  around  which  the  bight  of  a 
leash  is  placed;  this  leash  passes  through  the  ring  on  the  cable,  and 
is  permanently  fastened  to  the  grip  at  Q.  By  pulling  on  the  cord, 
the  finger  is  released,  and  the  leash  slips  out  of  the  ring  on  the  cable. 

Finally,  the  end  of  a rope  8 or  10  meters  long  and  from  0.015  to  0.018 
meter  in  diameter  which  may  be  called  the  leash,  is  permanently  at- 
tached at  Q.  The  other  extremity  is  free,  and  terminated  by  an  eye. 

To  hook  on  a boat,  the  grip  lying  on  the  towpath,  the  finger  D 
free,  a man  takes  the  free  end  of  the  leash  and  awaits  the  arrival  of 


the  shackle  A (Fig.  82),  and  passing  the  leash  through  the  shackle 
he  slips  the  ring  on  its  free  end  on  to  the  finger  D which  he  makes 
fast,  so  that  the  grip  is  arranged  as  in  Fig.  86.  A is  the  towrope, 
and  T the  leash,  going  through  the  cable  shackle.  This  done  he 
returns  to  the  boat  which  he  has  plenty  of  time  to  reach  before  the 
towrope  tightens.  If  he  wishes  to  stop,  he  attaches  the  grip  cord 
to  the  boat  and  slackens  the  towrope,  then  all  the  pull  coming  on 
the  grip  cord  the  spring  is  compressed,  the  finger  becomes  free, 
and  with  it  the  leash.  To  let  go  slowly  it  suffices  to  slacken 
the  rope  on  a bitt.  But  it  is  more  convenient  to  have  a wind- 
lass with  a brake  under  the  steersman's  foot;  the  brake  lever  is 
so  arranged  that  he  has  only  to  press  his  foot  down  to  tighten, 
and  to  let  it  go  to  loosen.  Thus  the  steersman,  without  quitting  his 
place,  by  a slight  motion  of  his  foot  upon  the  brake  casts  off  from 
the  cable.  To  slacken  speed  when  in  motion,  the  towrope  is  slack- 
ened, but  can  be  hauled  m again  by  the  windlass.  The  windlass  is 
especially  useful  for  this  purpose. 

Thus  the  slight  slowings  made  necessary  by  meeting  other  boats, 
or  passing  under  bridges,  are  immediately  made  up  and  the  journey 
is  made  with  mathematical  regularity. 


CIVIL  ENGINEERING,  ETC. 


631 


(112)  Method  of  circuits. — In  an  extended  application,  the  circuits 
may  cover  without  difficulty  a distance  of  from  15  to  18  kilometers, 
and  as  the  two  machines  driving  two  consecutive  circuits  may  he 
united,  it  follows  that  the  machines  may  be  from  30  to  36  kilometers 
apart. 

The  machines  thus  placed,  two  and  two  in  the  same  shed,  can 
mutually  help  each  other  in  case  of  accident  to  either.  Continuous 
towage  can  go  on  with  slightly  diminished  velocity,  it  is  true,  but 
with  no  stoppage. 

The  power  used  depends  on  the  velocity  desired.  With  a velocity 
of  0.70  meter  per  second,  the  velocity  of  horse  towage,  it  requires 
only  two  horse  power  to  draw  a barge  loaded  with  350  tons,  and  one 
horse  power  for  lighter  loads. 

If  we  adopt  the  velocity  of  one  meter  per  second,  we  must  multi- 
ply these  figures  by  2.25.  One-half  a horse  power  per  kilometer 
should  be  added  for  power  consumed  by  the  unloaded  cable.  Under 
these  conditions  for  a traffic  of  1,000,000  tons  per  year,  with  a velocity 
of  one  meter  per  second,  two  machines  of  from  45  to  50  horse  power 
would  be  required  for  each  distance  of  thirty  kilometers. 

(113)  The  cost  of  the  plant  depends  on  the  dimensions  of  the 
barges,  their  number  and  velocity. 

Assuming  the  largest  barges  38.50  meters,  with  a velocity  of  one 
meter  per  second,  and  a traffic  of  1,000,000  tons  per  year,  we  may 
estimate  the  cost  of  the  plant  at  17  francs  per  running  meter. 

The  cost  per  meter  of  working,  under  the  severest  conditions,  and 
including  a sinking  fund  for  the  capital,  and  the  cost  of  renewing 
the  cable  not  exceeding  3.18  francs,  the  expense  of  traction  is  0.003 
francs  per  ton  per  kilometer,  if  we  have  a traffic  of  1,000,000  tons; 
it  descends  to  0.0012,  if  the  traffic  amounts  to  2,500,000  or  3,000,000 
tons. 

This  system  has  been  devised  and  applied  between  Paris  and  Join- 
ville  by  M.  Maurice  Levy,  chief  engineer  of  roads  and  bridges. 

A system  of  cable  towage  differing  from  the  one  above  described, 
invented  by  M.  Oriville,  is  on  trial  on  the  Saint  Quentin  Canal,  at 
Tergniers. 

Chapter  XI. — Towage  by  a submerged  chain,  with  a fire- 
less ENGINE. 

(114)  The  summit  level  at  Mauvages  lies  between  the  two  slopes 
of  the  Marne  and  the  Meuse ; its  length  is  9,205  meters  of  which  4,877 
are  in  a tunnel. 

The  tunnel  consists  of  a full  central  arch  7.80  meters  in  diameter,- 
one  side  of  which  is  continued  by  a curved  lateral  wall;  on  the  other 
side  is  the  towpath,  1.40  meters  wide,  protected  by  a stone  revetment. 
The  bottom  is  about  G meters  wide.  The  pool  is  fed  at  low  water 


632 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


from  the  Oruain,  25,000  cubic  meters  per  day,  and  by  a set  of  pump- 
ing engines  at  Vacon,  furnishing  40,000  cubic  meters,  making  in  all 
65,000  cubic  meters  per  day. 

(115)  A system  of  chain  towage  has  recently  been  established  here 
with  towboats  driven  by  the  Francq-Lamb  system  capable  of  work- 
ing without  smoke.  The  Francq-Lamb  system,  the  invention  of 
Lamb  and  improved  by  Francq,  as  it  is  generally  employed  on  tram- 
ways, consists  in  using  steam  produced  from  water  at  a high  tem- 
perature contained  in  a reservoir  fed  at  some  point  on  the  road  from 
a fixed  source  of  supply.  It  includes,  independently  of  the  locomo- 
tive, a stationary  boiler,  with  a reservoir  of  superheated  steam  which 
may  be  used  at  starting,  or  at  some  point  on  the  road,  to  feed  the  fire- 
less locomotive.  This  system  thus  avoids  filling  the  tunnels  with 
smoke,  which  would  be  a serious  inconvenience. 

At  the  same  time  the  system  has  been  modified  by  placing  the  steam 
boilers  as  well  as  the  reservoirs  on  board  the  towboat.  This  arrange- 
ment, would  not  be  thought  of  for  a locomotive,  but  it  presents  no 
difficulty  on  a boat,  as  it  only  occupies  14  or  15  cubic  meters  of  space, 
and  the  additional  weight  is  unimportant. 

(110)  Description  of  the  boats  (Figs.  87  and  88,  A,  B,  D). — At 
the  bow  and  on  the  stern  are  two  guide  pulleys  for  the  chain.  Two 
boilers,  C,  with  safety  appliances,  rated  for  17  kilograms  of  effective 
pressure.  Abaft  the  engine  are  the  receivers  for  the  superheated 
water,  by  which  the  engine  is  driven,  when  the  boat  is  in  the  tunnel. 
Above  the  engine  are  the  drums  around  which  the  chain  passes. 

Fig.  88  shows  the  plan,  and  Figs.  A,  B,  and  D the  cross  sections 
through  the  receivers,  through  the  engine  and  chain  drum,  and 
through  the  boilers. 

Each  of  the  two  towboats  is  29  meters  long,  4.65  meters  wide,  and 
2.30  meters  deep.  The  hull  is  of  steel  plate;  its  draught  is  1.10  me- 
ters including  coal  and  water  for  a trip  of  9 kilometers  each  way. 

The  engine  is  placed  in  the  middle  of  the  boat;  at  one  end  are  the 
boilers  and  at  the  other  the  receptacles  for  the  superheated  water. 
The  effective  power  of  the  engine,  measured  on  the  first  towrope,  is 
18  horses.  It  is  a compound  condensing  engine  with,  two  inclined 
cylinders  furnished  with  reversing  gear. 

There  are  two  tubular  boilers  registered  for  17  kilograms  effec- 
tive pressure;  each  of  these  is  surmounted  by  a long  horizontal 
steam  chamber  united  to  it  by  large  openings;  the  water  level  rises 
just  into  these  chambers  which  carry  all  the  safety  apparatus.  On 
the  other  side  of  the  engine  are  the  superheated  water  receivers 
which,  with  the  generators,  furnish  the  steam  requisite  tor  work- 
ing the  boat  through  the  tunnel.  They  are  steel  cylinders  sur- 
mounted by  a dome  and  communicate  with  the  generators  by  a 
steam  pipe  and  cock  united  to  the  interior  of  the  reservoir  with  a 
perforated  pipe  for  heating  the  water. 


CIVIL  ENGINEERING,  ETC. 


633 


Before  it  is  sent  to  the  cylinders  the  steam  in  the  receivers  is 
brought  to  the  usual  pressure  of  5 or  G kilograms.  The  reser- 


voir for  the  expanded  steam  is  placed  in  the  interior  of  the  receptacle 
for  the  superheated  water,  thus  always  affording  very  dry  steam  for 
the  cylinders. 


Figs.  87.  and  88.  The  longitudinal  section  of  the  chain  tow  boats. 


634  UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 

The  expansion  apparatus  (for  regulating  the  pressure  of  the  steam 
to  be  admitted  into  the  cylinders)  is  moved  by  a working  beam  act- 
ing on  an  adjustable  lever  and  completely  regulating  the  use  of  the 
expanded  steam. 

The  mechanism  employed  is  exactly  that  used  in  the  Francq  loco- 
motives, except  that  the  generators  are  carried  by  the  boat  instead 
of  being  stationary. 

(117)  Daily  trips  of  the  boats. — Every  day  one  of  the  two  tow- 
boats makes  a trip.  Its  speed  is  2 kilometers  per  hour;  in  the  tun- 
nel it  is  reduced  to  1,500  meters,  and  often  1,200  meters  per  hour. 

Starting  at  7 o’clock  in  the  morning,  with  a pressure  of  5 or  6 
kilograms,  it  goes  an  hour  in  the  open  canal,  during  which  the 
pressure  augments  to  10  or  12  kilograms,  and  even  16  or  17  when 
the  load  is  very  heavy.  During  the  passage  through  the  tunnel, 
which  is  about  4 hours,  the  fire  is  allowed  to  fall,  and  the  boat  is 
driven  only  by  the  steam  in  the  receivers.  On  coming  out  of  the 
tunnel  the  pressure  has  fallen  to  4 or  5 kilograms,  which  is  suf- 
ficient to  finish  the  journey  in  the  open  canal,  which  usually  takes 
an  hour.  After  an  hour  for  rest  the  boat  returns  to  the  original 
starting  point. 

During  the  passage  through  the  tunnel  no  smoke  is  emitted,  so 
that  it  can  be  seen  through  from  one  end  to  the  other. 

The  boat  easily  tows  from  twenty  to  twenty-five  barges,  carry- 
ing 4,000  to  5,000  tons  of  useful  load,  with  the  effective  work  of  the 
engine  of  from  10  to  17  horse  power. 

The  coal  burned  with  a file  of  sixteen  barges  attached  does  not 
exceed  3 kilograms  per  horse  power,  per  hour,  measured  on  the  tow- 
rope  of  the  first  barge. 

The  toll  has  been  fixed  at  0.005  franc  per  ton  per  kilometer. 
The  number  of  hands  employed  is  six — two  engineers,  two  stokers, 
and  two  sailors;  one  of  the  four  in  the  engine  room  takes  a day  off 
to  rest  or  work  in  the  repair  shop. 

(118)  Cost. — The  total  cost  is  as  follows: 


Francs. 

First  towboat 120,000 

Second  towboat 143,000 

Chain 49, 000 

Sundries 63,000 


Total 375,000 


The  cost  of  working  is  about  20,000  francs,  which  is  largely  cov- 
ered by  the  tolls,  which  amount  to  about  24,000  francs  derived  from 
a traffic  of  600,000  tons  per  year. 

The  plans  were  prepared  under  the  direction  of  the  general  in- 
spector, Frdcot,  by  M.  Holtz,  chief  engineer. 


CIVIL  ENGINEERING,  ETC. 


635 


Chapter  XII.— System  for  supplying  the  canal  from  the 
Marne  to  the  Rhine  and  the  Eastern  Canal. 

(119)  Two  important  groups  of  pumps  serve  to  supply  the  canal 
from  the  Marne  to  the  Rhine  and  the  Eastern  Canal,  in  that  portion 
between  Toul  and  Mauvages,  the  summit  level  of  the  first  canal. 
These  establishments  are  those  of  Valcourt,  Pierre-la  Troiche,  and 
Vacon. 

(120)  The  establishments  of  Valcourt  and  Pierre-la  Treiche  are  sit- 
uated on  the  Moselle,  near  Toul;  they  use  the  falls  of  the  dams  con- 
structed for  the  canalization  of  that  river,  and  serve  to  supply,  during 
the  dry  season,  the  great  pool,  Pagny-sur-Meuse,  of  the  canal  from 
the  Marne  to  the  Rhine,  where  the  north  branch  of  the  Eastern 
Canal  takes  its  rise. 

Each  establishment  comprises  two  Fontaine  turbines,  each  driving 
three  horizontal  pumps.  The  connection  between  the  turbines  and 
pumps  is  made  direct  by  cranks  on  the  hollow  shafts  of  the  motors 
to  which  the  connecting  rods  of  the  pumps  are  attached.  (Figs.  89 
and  90.) 

The  six  pumps  of  each  establishment  send  their  water  to  a single 
air  reservoir  from  which  the  main  conduit  issues. 

The  data  applicable  to  these  establishments  are  as  follows: 


^ Height  of 
the  fall. 

Water  per  second. 

Power. 

Min. 

Max. 

Min. 

Max. 

Meters. 

Cu.  m. 

Cu.  TO. 

H.  P. 

H P. 

Valcourt  4 00 

3.25 

6.00 

173 

320 

Pierre-la  Treiche | 2.50 

6.50 

8. 125 

217 

270 

The  heights  to  which  the  water,  is  raised  are  40.  G5  meters  and 


40.20  meters. 

(121)  Cost. — 

Francs. 

Mach  ne  and  workshop  appliances 274, 600. 00 

Cost  of  laying  the  cast-iron  pipes,  including  the  cost  of  the  pipes 

themselves 248,173.33 

Pump  houses,  land,  etc 569, 192.23 

Other  expenses 542, 297. 75 


Total 1,634,262.31 


These  machines  annually  raise  5,000,000  cubic  meters  of  water. 
Allowing  6 per  cent  as  interest  and  sinking  fund,  we  find  0.48  franc 
as  the  cost  of  raising  annually  1,000  cubic  meters  of  water  1 meter. 
The  annual  expenses  of  working  100  days,  and  repairs,  are  20,000 
francs;  that  is,  for  1.000  cubic  meters  raised  1 meter,  0.10  franc;  if 
we  add  to  this  the  cost  of  the  establishment,  0.48  franc,  given  above, 
we  shall  find  the  total  cost  (0.58  franc)  of  raising  1,000  cubic  meters 
1 meter. 


636 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS, 


(122)  Establish  ment  at  Vacon. — The  other  establishment,  at  Vacon, 
consists  of  five  boilers,  two  horizontal  steam  engines,  and  two  hori- 
zontal piston  plunger  pumps,  raising  40,000  cubic  meters  per  day  a 
height  of  37  meters.  The  cost  of  the  establishment  was  1,250,000 


francs.  Making  the  same  calculations  as  before,  we  find  the  total 
cost  of  raising  1,000  cubic  meters  of  water  1 meter  by  steam  power 
to  be  0.93  franc.  The  two  sets  of  works  were  erected  under  the  di- 


CIVIL  ENGINEERING,  ETC, 


637 


■ 


rection  of  Inspector-General  Frdcot  by  Messrs.  Poincard,  Holtz, 
Bizalion,  and  Thoux,  chief  engineers,  and  M.  Picard,  assistant 
engineer. 


Fig.  90.—  Plan  of  the  pumping  station  at  Pierre-la  Treiche. 


638 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


-if"-.. 


Chapter  XIII. — Oscillating  bridge  over  the  Dames  Canal 

Lock. 

(123)  A very  common  arrangement  in  canals  consists  in  placing  a 
permanent  bridge  on  the  lower  end  of  a iock,  using  the  tail  walls  as 
abutments. 

This  arrangement,  though  economical  in  construction,  is  an  obsta- 
cle in  working,  especially  in  ascending,  by  obliging  the  driver  to 
untackle,  that  is,  to  suspend  the  traction  precisely  at  the  moment 
when  the  traction  should  be  greatest  to  overcome  the  resistances  to 
the  boat’s  entrance  to  the  lock. 

To  remedy  this  difficulty  a new  type  of  movable  bridges  has  been 
introduced,  called  an  oscillating  bridge.  One  of  these  has  lately 
been  built  over  the  Dames  Lock  on  the  Nivernais  Canal,  which 
gives  great  satisfaction  to  the  boatmen. 

Fig.  91  shows  the  principle  of  the 
bridge;  the  hatched  edges  are  sec- 
tions of  the  bridge  abutments  ; A B 
is  the  iron  roadway  movable  around 
a horizontal  axle  O,  placed  a few 
fig.  91-Diagram  of  the  bascule  bridge,  centimeters  back  from  the  abutment 
face  (on  the  side  opposite  the  towpath),  and  divided  by  this  axle  into 
two  unequal  parts  O A and  O B,  the  first  about  double  the  second. 
When  the  roadway  is  in  its  normal  position  the  extremity  A rests  on 
the  abutment  on  the  towpath  side,  while  the  other  is  held  on  a level 
with  the  coping  by  a particular  system  of  sliding  bolts.  This  abut- 
ment contains  a little  depression,  so  that  the  roadway  may,  by  tip- 
ping, take  the  position  A'  B '.  The  towrope  passing  between  A and 
A'  obviates  the  necessity  of  untackling,  and  thus  renders  the  traction 
continuous.  An  oscillation  in  the  contrary  direction  brings  back 
the  roadway  to  its  normal  position,  A B.  The  roadway  has  a fixed 
and  a movable  counterpoise,  and  when  these  are  properly  adjusted 
and  the  sliding  bolts  pulled  out  by  means  of  a lever  arranged  for  the 
purpose  the  bridge  is  opened  by  the  weight  of  a man  at  B,  and  by 
his  weight  at  A closed  and  locked  by  the  sliding  bolts. 

This  system  is  due  to  M.  B de  Mas,  chief  engineer  of  roads  and 
bridges. 


Chapter  XIV.— Balanced  gates  on  the  Rhone  and  Cette 

Canal. 

(124)  The  Rhone  and  Cette  Canal  crosses  the  Lez  River  through  a 
circular  basin  50  meters  in  diameter,  1,500  meters  from  the  mouth 
of  the  river  in  the  Mediterranean. 

Until  1886  the  two  branches  of  the  canal,  one  the  prolongation  of 
the  other  through  the  basin,  were  terminated  by  two  openings 


CIVIL  ENGINEERING,  ETC. 


639 


reduced  to  6.60  meters  in  width,  called  semi-locks,  which  were  closed 
with  a plank  dam  during  the  time  of  freshets  in  the  river.  These 
freshets,  though  short  and  infrequent,  could  not  be  foreseen ; they 
came  frequently  at  night. 

The  closing  of  the  canal  required  a number  of  hands,  which  were 
not  easily  obtained  at  a short  notice,  and  the  work  took  from  three 
to  four  hours  for  each  opening.  If  the  openings  were  not  closed  in 
time  large  quantities  of  silt  were  deposited,  which  on  some  occa- 
sions have  interrupted  the  traffic  for  a month.  The  annual  amount 
of  dredging  exceeded  12,000  cubic  meters,  costing  more  than  15,000 
francs  per  year  on  account  of  the  insufficient  method  of  closing  the 
openings. 

To  the  effect  of  the  river  must  be  added  that  of  the  sea.  The 
water,  driven  in  by  gales  of  wind,  is  forced  up  the  river  like  a tide, 
and,  spreading  through  the  openings  into  the  canal,  leaves  additional 
masses  of  sand  to  be  dredged  out. 

The  frequency  of  these  storms,  together  with  the  impossibility  of 
keeping  the  openings  closed,  on  account  of  the  traffic,  has  led  to  the 
adoption  of  balanced  gates  of  a new  type  at  the  river  crossing. 

(125)  The  programme  was  as  follows:  To  construct  at  each  open- 
ing a cheap  work,  utilizing  the  existing  masonry  walls  and  fulfilling 
the  following  conditions : 

First.  The  openings  must  be  closed  at  any  height  of  the  water  by 
one  man  in  a very  short  time. 

Second.  They  must  be  able  to  be  opened  under  a head  of  from 
0.50  to  0.75  meter  by  two  men  in  a few  minutes. 

Third.  The  vertical  section  of  the  space  to  be  closed  is  7.65  meters 
wide  by  3.60  meters  high  ; the  maximum  head  of  water  from  a 
freshet  to  be  1 meter. 

Fourth.  In  the  normal  condition  there  must  be  a free  passage 
the  whole  width,  6.60  meters,  of  the  opening,  a draught  of  2.40  me- 
ters, and  a vertical  opening  from  3.80  to  3.90  meters  above  the  water 
line. 

Fifth.  A final  condition  for  the  preservation  of  the  work  was  that 
nearly  all  the  pieces  of  metal  or  wood,  and  the  mechanical  appli- 
ances, should  be  normally  out  of  water,  and  that  when  immersed 
they  should  spontaneously  emerge,  both  for  inspection  and  repair. 

(126)  Description  of  the  gates. — The  work  consists  of  a cylindrical 
sluice  turning  about  a horizontal  axle  with  little  friction.  This  cylin- 
der has  a radius  of  3.80  meters  and  consists  of  a plate-iron  skin  0.008 
meter  thick,  7.65  meters  wide,  with  a developed  length  of  4.20  meters 
along  its  right  section.  It  is  riveted  on  four  horizontal  double  T 
flanges  1.05  meters  apart.  The  whole  is  braced  internally  by  special 
irons.  The  end  generatrices  of  the  skin  are  strengthened  by  lon- 
gitudinal angle  irons ; the  one  intended  to  strike  against  a hurter  in 
the  flooring  serves,  besides,  to  increase  the  surface  of  contact. 


640 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


The  sluice  thus  constructed  is  supported  at  each  end  by  a number 
of  iron  double  T arms  coming  together  in  each  side  of  the  opening 
in  the  hollow  quoin  prepared  in  the  masonry  for  the  axle,  to  which 
they  are  united  by  a cast-iron  hub.  These  arms,  four  in  number  on 
each  side,  are  united  at  right  angles  to  the  corresponding  flanges. 
The  junction  of  the  arms  with  the  outer  skin  and  flanges  is  com- 
pleted by  an  iron  plate  cut  in  in  the  form  of  the  segment  of  a circle 
and  riveted  flat  upon  the  arms,  and  edgewise  on  the  projecting  skin, 
by  means  of  a curved  angle  iron. 

The  wrouglit-iron  axles,  0.25  meter  in  diameter,  are  inserted  1 
meter  above  low  water  into  cast-iron  hubs,  and  each  one  rests  on  two 
pillow  blocks,  one,  the  bearing  pillow  block,  close  to  the  masonry, 
the  other  2. 50  meters  behind.  These  axles  are  perpendicular  to  the 
chamber  walls. 


To  balance  the  gate  around  its  axle,  a cast-iron  segment  of  a rim 
is  placed  on  each  side  opposite  the  sluice,  its  weight  being  accurately 
calculated.  Each  counterpoise  is  united  to  the  hub  by  two  arms  in 
line  with  those  connecting  the  edges  of  the  sluice.  This  arrange- 
ment balances  the  structure  if  it  is  completely  immersed  in  air  or 
water.  In  reality,  part  must  be  in  and  part  out  of  water.  At  the 
moment  when  the  lower  side  of  the  sluice  enters  the  water,  and 
where  the  counterpoise  emerges,  there  is  produced,  in  virtue  of  the 
Archimedean  principle,  athruston  onesideand  adiminutionof  thrust 
on  the  other,  the  moments  of  which  add  and  constitute  a consid- 
erable resistance  to  the  motion,  attaining  as  a maximum  5,000  or 


CIVIL  ENGINEERING,  ETC. 


641 


6,000  kilograms  at  the  distance  of  1 meter.  This  effort,  eight  or  ten 
times  the  passive  resistance  of  friction,  would  destroy  the  advantages 
of  the  system.  The  following  simple  arrangement  removes  the 
whole  difficulty.  The  additional  resisting  moment  due  to  the  up- 
ward pressure  of  the  water  at  any  instant  will  evidently  he  annulled, 
if  an  equal  and  upward  thrust  is  produced  symmetric  with  the  axis 
of  rotation;  the  total  resultant  will  pass  through  the  axis  and  tend  to 
lift  it,  and  thereby  diminish  the  friction. 

A wooden  rim  completing  that  formed  by  the  counterpoise  and 
the  sluice,  calculated  so  that  the  moment  of  its  volume  per  unit  of 
angle  shall  be  equal  to  the  mean  moment  of  the  sluice,  including  the 
arms,  etc.,  solves  mathematically  the  case  of  the  plane  of  flotation 
passing  through  the  axis,  and  approximately  for  the  case  of  any 
plane  of  flotation.  * 

Each  portion  of  the  wooden  crown,  formed  of  two  segments  of  one- 
sixth  of  the  circumference,  is  united  at  one  end  to  one  of  the  outside 
arms  of  the  sluice;  and  at  the  other  end  to  an  arm  of  the  counter- 
poise. It  is  strengthened  in  the  middle  by  another  double  T arm 
fixed  to  the  hub  perpendicular  to  the  mean  radius  of  the  sluice. 

Iron  hanging  ties,  strongly  stretched,  complete  the  connection  and 
give  great  stiffness  to  the  wheels  thus  formed,  which  are  contained 
in  the  hollow  quoins  and  thus  protected  from  the  shock  of  the 
barges. 

With  a view  of  rendering  the  closing  of  the  sluice  easier  than  the 
opening,  the  theoretical  equilibrium  has  been  voluntarily  broken, 
by  hollowing  those  ends  of  each  counterpoise  which  emerge  first 
during  the  closing. 

Finally,  the  intermediate  arms  sustaining  the  wooden  crowns, 
which  are  horizontal  in  their  normal  position,  can  be  fastened  on 
the  upstream  end  by  movable  wooden  wedges,  and  on  the  down- 
stream side,  by  strong  wrought-iron  bolts  so  as  to  prevent  the  gate 
from  being  accidentally  displaced.  In  closing,  the  cylindrical  sluice 
strikes  its  lower  edge  against  an  oak  hurter  2.10  meters  below  low- 
water  mark,  and  the  upper  edge  is  at  1.50  meters  above  that  limit. 

(127)  The  opening  and  closing  are  easily  effected  by  means  of  two 
chains  passing  around  a groove  in  the  rim  of  the  wooden  crowns 
and  counterpoises  and  pulled  in  one  direction  or  the  reverse  by 
means  of  chain  pulleys  worked  by  windlasses.  Generally  the  wind- 
lasses are  thrown  out  of  gear.  To  start  the  gate,  the  wedges  are  re- 
moved, the  bolts  opened,  and  one  of  the  windlasses  is  put  in  gear 
and  worked  (by  one  man,  who  makes  the  opening  in  forty  or  sixty 
seconds  ; to  open  the  gate  under  a head  of  0. 50  or  0. 75  meter,  both 
windlasses  are  used,  and  two  men,  one  on  each  side,  effect  the  opera- 
tion in  five  or  six  minutes. 

* This  ring  being  there  for  the  sake  of  its  volume,  and  not  for  weight  or  strength, 
the  use  of  wood  is  naturally  indicated. 

H.  Ex.  410 — VOL  III 41 


642 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


This  apparatus  solves  completely  the  problem,  and  assures  rapid 
opening  and  closing  of  the  two  openings  in  times  of  freshet  or  high 
tide.  Although  recently  established,  there  has  been  considerable 
diminution  in  the  silting,  and  in  the  interruptions  in  the  traffic. 
These  interruptions  were  formerly  for  several  consecutive  days  per 
year,  now,  they  amount  to  a few  hours  for  each  freshet,  and  general- 
ly the  boats  can  pass  notwithstanding*  an  ordinary  freshet.  The 
solution  is  therefore  perfectly  satisfactory. 

(128)  Cost. — The  iron  frame-work  of  the  two  gates  with  their 
accessories,  hurters,  windlasses,  etc.,  including  the  cost  of  setting 
up,  amounted  to  27,295.54  francs.  It  was  begun  in  1885  and  finished 
in  1887. 

The  plan  was  made,  and  the  work  executed  by  M.  Guibal,  engi- 
neer, under  the  direction  of  MM.  Delon  and  Lenthdric,  successive 
chief  engineers. 

Chapter  XV.— Braye-en-Laonnois  Tunnel. 

(129)  An  example  of  the  use  of  compressed  air  in  tunnel  construc- 
tion.— The  canal  between  the  Oise  and  the  Aisne  passes  through  the 
ridge  separating  the  basins  of  these  two  rivers,  by  a tunnel  2,360 
meters  long,  the  bottom  being  at  a distance  of  122  meters  below  the 
highest  point. 

The  geological  formation  is  that  portion  of  the  Tertiary  known 
as  the  Eocene,  and  the  stratum  the  Suessonian.  This  Suessonian 
stratum  is  made  up  of  a layer  of  plastic  clay  between  two  layers  of 
sand,  viz,  the  Soissonnais  above  and  the  Bracheux  below.  Above  the 
Soissonnais  sand  comes  the  Paris  chalk  which  constitutes  the  ridge. 

The  tunnel  is  driven  through  the  lower  layers  of  the  Suessonian; 
but  near  the  head  on  the  Oise  slope  the  layers  form  a pocket,  the 
point  of  which,  300  meters  from  the  head,  penetrates  the  crown  of 
the  tunnel  for  a distance  of  0.30  meter  into  the  layer  of  Tertiary 
Soissonnais  sand.  The  water  filtering  through  the  upper  sands  ac- 
cumulates upon  the  layer  of  clay,  and  at  the  beginning  of  the  work 
filled  the  ground  for  a height  of  15  or  16  meters,  and  rendered  these 
sands,  which  are  very  fine,  liquid.  Also,  the  water  soaked  into  the 
upper  part  of  the  layer  of  plastic  clay,  which,  besides  the  imperme- 
able clay  beds,  contained  permeable  beds  of  lignites  and  agglomera- 
tions of  shells. 

In  these  formations  on  the  Oise  slope  the  driving  of  the  tunnel 
presented  the  greatest  difficulties,  increasing  as  the  thickness  of  the 
clay  roof,  which  served  as  a protection  against  the  fluid  sand,  dimin- 
ished. At  each  instant  thin  layers  of  clay,  intercalated  between  the 
lignites  and  the  shell  agglomerates,  kept  breaking,  resulting  in  cav- 
ings in  and  inpourings  of  sandy  mud,  stopping  the  work. 

(130)  Use  of  compressed  air. — To  remedy  this  state  of  things  it 
was  proposed  to  use  compressed  air,  and  the  plant  for  this  purpose 


643 


CIVIL  ENGINEERING,  ETC. 

was  thus  set  up  near  the  head.  It  consists  of  seven  portable  engines 
of  220  horse  power,  driving  eight  compressors,  which,  furnish  to  the 
working  chamber,  every  24  hours,  50,000  cubic  meters  of  air  under 
a pressure  of  1 kilogram  above  the  atmosphere. 


' 1 1 1 l-M . . 1 1 1 

o 10  xo  30  So  50  _ 

O *00  X00  100  *100  Soo  too  JO0  Soj  yoo  iooo* 

Fig.  93.— Geological  section  of  the  range  of  hills  between  the  Oise  and  Aisne  valleys  through  the  axis 
of  the  tunnel.  The  upper  layer  is  miry  clay:  the  next  is  limestone  rock;  then  Soissonnais  sand 
down  to  the  dark  stratum:  the  curved  line,  marked  101,  denotes  the  water  level.  Below  the  sand 
is  a stratum  of  dark  clay  containing  lignites,  which  ignited  when  the  water  was  driven  off.  Below 
this  is  a stratum  of  compact  blue  clay,  and  just  in  a pocket  projecting  down  into  the  tunnel  is  a 
mass  of  Soissonnais  sand.  Below  the  blue  clay  is  a mass  of  Braeheux  sand.  The  portion  of  the 
tunnel  giving  the  greatest  difficulty  and  requiring  the  use  of  compressed  air  is  situated  between  185 
and  450  meters  from  the  head. 

In  front  of  the  machinery  building  a series  of  reservoirs  was  set 
up  of  91  cubic  meters’  capacity,  with  the  air  at  a pressure  of  from 
4 to  G kilogrammes  (absolute  pressure)  which  served,  especially  in 
the  beginning,  to  drive  out  the  excavated  material,  as  will  be  ex- 
plained presently. 


644 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


The  working  chamber  at  the  face  of  the  tunnel  was  formed  by  a 
masonry  wall,  perforated  by  air  locks  (Fig.  95)  giving  admittance 
to  and  exit  from  the  chamber. 


(131)  The  first  wall  or  dam  was  10  meters  thick  and  120.50  meters 
from  the  head ; but  the  second,  which  was  at  187  meters  from  the 
head,  will  be  here  described,  as  it  was  an  improvement  on  the  first: 


Fiq.  94.— Details  of  the  construction  of  the  tunnel.  Longitudinal  section  along  the  axis  A B of  the  tunnel.  Horizontal  section  plans  along 

A B and  O P.  Cross  sections  C D,  E F,  G H,  I J,  K L,  M N. 


CIVIL  ENGINEERING,  ETC. 


645 


This  dam  was  formed  by  a wall  6.70  meters  thick  above  and  8 me- 
ters below,  so  as  to  contain  the  lock  and  pieces  of  frame  work,  which 
had  to  project  into  the  working  chamber.  It  was  constructed  of 
bdton  held  by  masonry  walls.  Five  openings  were  made,  three 
below  and  two  above,  the  lower  ones  only  being  supplied  with  locks, 
the  upper  ones  being  closed  by  a stone  wall. 


« 


Sections  of  the  air  lock. 

Fig.  95—  A,  air-supply  pipe;  B,  pipe  enclosing  the  electric  wires;  C,  pipe  inclosing  the  telephone  wires; 
D,  pipe  for  discharging  the  excavation  spoil;  E,  drain  pipe;  F,  entrance  of  the  high-pressure  air  pipe, 
used  to  blow  out  the  excavation  spoil.  Fig.  96  is  the  section  through  the  broken  line  A B.  The  lower 
cylinder  is  the  air  lock  ; the  curved  tube,  marked  F,  at  one  end  was  used  to  blow  out  the  excavation 
spoil. 

Each  lock  was  8 meters  long,  1.65  meters  wide,  and  2.20  meters 
high  ; it  was  provided  with  a lining  consisting  of  wrought  iron  rings, 
with  India  rubber  washers,  bolted  together,  and  with  two  air  tight 
doors  closing  against  seats  faced  with  India  rubber,  one  opening 
from  the  outer  air  into  the  lock,  and  the  other  from  the  lock  into 
the  chamber;  the  latter  could  be  opened  from  within  the  lock  or 
from  the  working  chamber  by  means  of  a double  set  of  levers  for 
that  purpose.  Above  each  door,  cocks  were  placed,  one  on  the  inte- 
rior and  one  on  the  exterior  of  the  lock,  for  the  introduction  or  escape 
of  the  compressed  air. 

(132)  Mode  of  removing  the  excavation  sjioil. — The  lock  had  a 
small  railroad  track,  and  cars  could  be  carried  through  it;  four  pipes 
also  passed  through  it,  two  above  and  two  below.  These  pipes,  0.40 
meter  in  diameter  and  inclined  O.05  meter  per  meter,  ended  in  the 
working  chamber  by  an  upward  bend  into  which  the  spoil  was 
thrown.  Each  end  of  this  pipe  was  tightly  closed  by  a stop  valve. 
The  exterior  valve  being  closed,  the  pipe  was  filled  from  the  interior, 
then  closing  the  interior  valve,  opening  the  exterior,  and  at  the 
same  time  opening  a cock,  putting  the  curved  portion  of  the  pipe  in 
connection  with  the  pipe  bringing  air  from  the  reservoirs  at  a 
pressure  of  at  least  4 kilograms,  this  pressure  drove  out  the  spoil 
in  a few  seconds.  The  exterior  valve  was  then  closed  and  the  opera- 
tion repeated. 


646 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


Two  drain  pipes  0.35  meter  in  diameter  passed  through  the  lock 
on  the  floor;  they  had  cocks  which  served  for  the  drainage  of  the 
chamber,  the  water  being  driven  out  by  the  compressed  air. 

Gramme  dynamos,  driven  by  a 15  horse-power  engine,  supplied 
the  Edison  lamps  for  lighting  the  chamber,  and  a telephone  united 
it  with  the  central  office. 

Great  difficulties  were  found  in  keeping  the  working  chamber 
tight.  The  compressed  air  forced  its  way  out  over  the  extrados  of 
the  arch,  between  the  masonry  and  the  earth,  along  poling  boards 
required  for  supporting  the  ground,  and  also  through  the  masonry 
joints.  It  was  only  by  building  a masonry  buttress,  from  40  to  50 
centimeters  thick,  that  the  pressure  in  the  chamber  could  be  brought 
up  to  1.8  or  2 kilograms,  under  which  condition  the  arch  was  com- 
pleted, for  a distance  of  200  meters  from  the  head,  at  the  rate  of  12 
or  15  meters  per  month. 

(133)  Accidents  by  fire. — In  August,  1884,  the  work  was  arrested 
by  an  accident  which  cost  the  lives  of  seventeen  workmen.  The 
compressed  air  had  penetrated  into  the  pyrites  lignites,  driven  off 
the  water,  and  oxidized  the  pyrites;  the  heat  thus  produced  had 
ignited  the  lignites,  and  the  gas  from  this  combustion  had  asphyx- 
iated the  victims. 

(134)  Accessory  constructions. — To  reestablish  access  to  the  lock 
another  issue  was  opened  for  the  products  of  the  gas  combustion,  by 
making  six  vertical  bore  holes,  starting  from  the  outside  and  carry- 
ing them  to  the  points  where  the  fire  was  most  active.  On  the  other 
hand,  the  finished  part  of  the  tunnel  was  ventilated  by  compressed 
air  carried  into  the  air  lock  and  allowed  to  escape.  After  awhile  the 
air  became  pure,  and  on  the  4th  of  October  the  ground  in  the  work- 
ing chamber  was  shored  up,  and  on  the  30tli  the  forced  ventilation 
by  compressed  air  was  discontinued.  The  surface  water,  no  longer 
kept  back,  penetrated  to  the  seat  of  the  fire  and  extinguished  it; 
but  this  water  remained  hot  a long  time;  six  months  after,  that 
which  trickled  through  had  a temperature  of  30°  C.  It  was  at  this 
time  that  the  lock  was  transferred  from  120.50  to  187  meters  from 
the  head,  as  above  described. 

As  the  combustion  of  the  lignites  was  always  to  be  feared,  provi- 
sion was  made  for  securing  an  active  ventilation  through  the  whole 
of  the  open  tunnel,  by  sinking  a shaft  a little  on  one  side  and  con- 
necting it  with  the  crown  of  the  arch  by  a short  inclined  drift  109 
meters  from  the  head.  This  shaft  was  closed  at  the  top  and  pro- 
vided with  a Pelzer  fan  1.80  meters  in  diameter,  with  a minimum 
exhausting  capacity  of  15  cubic  meters  per  second.  (See  Fig.  97). 

That  the  suction  of  the  fan  should  be  felt  in  front  of  the  lock  the 
tunnel  was  divided  into  two  unequal  parts  by  a vertical  longitudinal 
wall  1.80  meters  from  the  right  wall  of  the  tunnel  surrounding  the 
ventilation  mouth,  and  prolonged  to  within  4 meters  of  the  lock. 


CIVIL  ENGINEERING,  ETC. 


647 


The  work  with  compressed  air  was  recommenced,  but  it  was  very 
difficult  to  keep  up  the  pressure,  and  it  was  determined  to  interrupt 
the  construction  for  a certain  length  and  begin  20  meters  farther  on, 
so  as  to  leave  a massive  dam  of  unbroken  ground  between  the  old 
and  new  chamber.  For  this  purpose  both  compartments  of  the  old 
working  chamber  were  closed  by  masonry  walls. 

To  permit  the  continuation  of  the  work,  three  arched  galleries 
were  driven,  two  below  on  a level  with  the  flooring,  and  one  above 


(Fig.  94),  but  the  upper  one  had  to  be  immediately  closed  on  account 
of  leaks.  The  lower  galleries  being  driven  through  clay,  no  leaks 
were  perceived  after  they  had  been  lined  with  masonry,  one  for 
24.50  meters  and  the  other  for  10.25  meters  of  their  respective  lengths. 

The  pressure  went  up  as  the  work  advanced  from  2.3  to  2.4  kilo- 
grams with  two-thirds  of  the  motive  power,  and  this  was  the  normal 
pressure  used  in  completing  the  work.  In  this  way  the  driving 
of  the  lower  galleries  continued  until  the  bottom  of  the  pocket,  300 
meters  from  the  head,  had  been  passed,  then  they  turned  back 


648 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


toward  the  head  and  constructed  the  arch  upon  the  abutments  built 
by  the  aid  of  the  lower  galleries.  This  step  was  successful,  and 
allowed  the  work  to  be  finished. 

Details  of  the  ivork. — While  the  lower  arched  galleries  were  being 
driven  the  lower  story  of  the  abutments  of  the  arch  between  the 
references  63.20  and  G5.85  meters  was  built ; then,  when  the  galleries 
were  recommenced,  by  means  of  timbering  they  constructed  in  the 
same  way  the  lower  story,  which  formed  one  of  the  side  walls  of  the 
gallery.  In  the  beginning,  the  other  wall  on  the  shaft  side  was 
simply  protected  with  poling  boards,  but  the  swelling  of  the  clay  which 
broke  the  timbers,  reduced  the  section,  and  stopped  the  running  of 
the  cars,  obliged  them  to  build  on  this  side  a wall  0.G0  meter  thick, 
strengthened  by  spurs  1 meter  thick  and  1.50  meters  apart.  These 
little  walls  were  constructed  for  the  whole  length  of  the  lower  gal- 
leries. These  galleries  also  served  to  construct  another  story  of 
abutments  between  the  references  65.85  and  68.40  meters,  which  was 
built  by  means  of  a gallery  driven  astride  the  lower  abutment;  see 
Fig  04,  section  KL.  The  communication  between  the  two  galleries 
was  made  by  the  space  between  the  timbering,  by  taking  out  the 
horizontal  shores  between  two  frames. 

This  upper  gallery  was  open  for  a length  of  10  meters  at  a time  ; 
they  laid  the  masonry  abutments  at  one  end,  and  drove  the  gallery 
at  the  other,  changing  the  connecting  apertures  with  the  lower  gal- 
lery as  they  advanced.  As  soon  as  the  masonry  work  was  finished, 
they  filled  the  rest  of  the  gallery  with  blocks  of  dry  stone  so  as  to 
allow  no  space.  This  work  went  on  at  the  rate  of  1.50  meters  per 
day,  occasionally  interrupted  by  the  ignition  of  the  lignites.  When 
they  arrived  at  a point  397  meters  from  the  head  a rise  was  put  in, 
and  a length  of  4 meters  of  the  arch  completed.  From  this  point 
the  work  was  carried  on  in  both  directions,  but  principally  toward 
the  Oise,  at  the  rate  of  12  meters  per  month. 

The  layer  of  fluid  sand  extended  0.50  meter  into  the  top  of  the 
upper  gallery,  but  it  had  become  so  dry  by  the  action  of  the  com- 
pressed air,  that  they  were  able  to  put  in  the  crown  packing  planks, 
one  at  a time,  after  making  a space  with  a spade  and  driving  it  in 
with  a mallet.  The  water  did  not  begin  to  run  until  these  planks 
were  put  in,  and  owing  to  the  opening  of  the  lower  galleries  its  level 
had  fallen  5 or  G meters,  which  facilitated  the  work. 

While  the  work  of  finishing  the  arch  toward  the  Oise  continued, 
it  was  slowly  progressing  toward  the  Aisne.  On  the  25th  of  Septem- 
ber, 1888,  the  arch  having  been  completed  to  409.50  meters,  the  use 
of  compressed  air  was  discontinued  and,  on  account  of  the  rising  of 
the  beds  of  clay,  the  rest,  up  to  450  meters,  was  finished  without  it, 
by  taking  proper  precautions. 

(135)  Cost. — The  first  450  meters  of  the  tunnel  were  finished  in 
Octobei*,  1888,  and  cost  6,720  francs  per  running  meter. 


CIVIL  ENGINEERING,  ETC. 


649 


The  work  was  done  under  the  direction  of  M.  Boeswillwald,  chief 
engineer  of  roads  and  bridges,  and  M.  M.  Guillon  and  Pigache, 
assistant  engineers. 

Chapter  XVI. — Navigation  of  the  Seine  from  Paris  to  the 

sea. 

(136)  At  the  beginning  of  the  century  the  navigation  of  the  Lower 
Seine  was  often  interrupted  by  low  water  and  by  freshets.  Great  diffi- 
culties and  even  dangers-were  encountered  in  passing  the  bridges  and 
dams.  Ascending  only  by  horse  towage,  consuming  from  Rouen  to 
Paris  fifteen  days  for  ordinary  freight,  and  four  or  five  for  accelerated 
freight,  the  boats  were  rarely  able  to  be  loaded  to  their  full  depth, 
from  1.80  to  2 meters.  The  cost  of  freight  was  16  francs  per  ton  from 
Rouen  to  Paris,  and  the  annual  traffic  did  not  exceed  77,000,000 
kilometric  tons. 

Without  undertaking  to  describe  the  improvements  made  in  the 
navigation  of  the  river  before  1878,  it  is  sufficient  to  say  that  with 
the  works  recently  constructed,  many  of  which  have  been  described 
in  detail,  the  river  between  Paris  and  Rouen  has  been  divided  into 
nine  reaches  by  the  construction  of  locks  and  dams,  with  a minimum 
draught  of  water  of  3.20  meters,  and  no  difficulties  are  experienced 
either  from  low  water  or  the  passage  of  locks.  The  towpaths  are 
in  order,  but  they  have  been  abandoned,  the  transport  being  made  by 
steam,  either  by  freight  boats  or  towboats;  the  journey  is  made  by  the 
former  in  28  hours,  and  by  the  latter,  towing  a convoy,  in  3 days. 
The  price  of  freight,  which  was  from  12  to  15  francs  per  ton  in  1840, 
10  to  12  in  1859,  8 to  9 in  1869,  is  now  from  4 to  5 ascending,  and 
from  2.75  to  3.50  francs  descending,  and  will  diminish  progressively 
as  new  boats  are  built  to  utilize  more  completely  the  improvements 
of  the  route. 

Indeed,  the  traffic*  since  the  completion  of  the  canalization,  has 
considerably  augmented.  The  total  tonnage  between  Paris  and 
Rouen,  including  that  taken  on  the  way,  was  in  1881,  227,307,266  kilo- 
metric  tons,  and  in  1888  it  was  389,668,346. 

(137)  Cost. — The  cost  of  the  works  of  canalization  amounts  to 
88,553,000  francs.  If  we  compare  this  total  expense  with  the  actual 
traffic  we  find  the  interest  at  5 per  cent  on  the  first  cost,  divided  by 

the  number  representing  this  traffic  to  be,  5 x-8S— 000  = 0.011 

100  389,568,346 

per  kilometric  ton,  and  it  is  certain  that  the  cost  of  freight  has 
diminished  very  much  more  than  that. 

All  the  works  constructed  from  1878  to  1888  were  directed  by  MM. 
de  Lagrend,  Bould,  and  Camere,  chief  engineers. 


* M.  Camere  pointed  out  to  the  author  a new  steamer  of  600  tons  burden,  built 
for  the  coasting  trade,  just  returned  from  a voyage  to  Spain. 


650 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


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CIVIL  ENGINEERING,  ETC. 


651 


Chapter  XVII — Embankment  works  for  the  improvement  of 

the  tidal  Seine. 

(13?)  The  object  of  the  improvement  of  the  tidal  Seine  is  to  facili- 
tate the  access  of  vessels  to  the  port  of  Rouen,  situated  125  kilometers 
from  the  sea.  Of  this  distance  half  required  improvements  to  render 
it  navigable,  and  this  comprised  the  parts  between  La  Mailleraye 
and  the  sea  below  Honfleur.  The  breadth  of  the  river  bed  between 
La  Mailleraye  and  Villaquier  was  1,000  meters,  at  La  Vacquere  1,500 
meters,  at  Quillebeuf  3,000,  below  La  Roque  7,000,  and  above  Hon- 
fleur 10,000  meters  (Fig.  98). 

(138)  Depth  of  ivater. — This  vast  extent  of  water  was  filled  with 
banks  of  shifting  sand,  which  were  constantly  changing  place 
through  the  action  of  the  strong  currents  of  the  ebb  and  flow  of 
the  tide,  and  it  often  happened  that  in  the  course  of  a few  days 
the  position  of  the  channel  would  be  shifted  from  one  side  of  the 
river  to  the  other.  The  depth  was  also  variable  and  insufficient. 
During  the  highest  tides  there  was  a depth  of  4.30  meters  below 
Quillebeuf,  and  only  1.76  meters  at  high  neap  tides,  and  many  dan- 
gerous rocks  and  shoals  impeded  the  navigation  above  this  point. 
These  perils  encountered  at  intervals  of  the  voyage  were  considera- 
bly augmented  by  the  tidal  wave  or  bore,  and  vessels  were  stranded 
by  its  powerful  action  without  the  possibility  of  receiving  assistance. 
Under  these  circumstances  the  navigation  was  confined  to  vessels 
of  from  100  to  200  tons  burden.  The  voyage  from  the  sea  up  to 
Rouen  occupied  four  days;  a great  number  of  wrecks  marked  the 
route,  freights  between  the  sea  and  Rouen  rose  to  10  francs  per  ton, 
and  the  rate  of  insurance  was  one-half  per  cent. 

(139)  Improvements. — Such  was  the  state  of  things  in  1848,  when 
the  improvements  were  begun,  which  consisted  in  building  training 
walls,  sometimes  on  one  side,  sometimes  on  both  sides,  extending 
from  La  Mailleraye  to  the  mouth  of  the  Risle,  a distance  of  43  kilo- 
meters. The  distance  between  the  training  walls  was  300  meters  at 
La  Mailleraye,  and  gradually  increased  to  500  at  the  Risle.  Tow- 
paths  were  built  between  La  Mailleraye  and  Rouen.  The  works 
were  finished  in  1867  and  cost  about  14,000,000  francs. 

These  training  walls  are  constructed  of  random  work  built  of 
blocks  of  chalk  taken  from  the  cliffs  on  the  banks  of  the  river  ; some 
are  raised  above  the  level  of  the  highest  tides,  while  others  are 
capable  of  being  submerged,  so  that  they  may  have  less  influence 
in  promoting  the  accumulation  of  deposits.  High  walls  are  used 
on  the  right  bank  as  far  as  Tancarville,  and  on  the  left  as  far  as  La 
Roque.  Beyond  these  points  the  walls  are  low.  At  La  Roque  the 
top  of  the  wall  is  1.34  meters  above  low  water  at  neap  tides,  and 
2.10  meters  above  low  water  at  the  spring  tides.  The  right  embank- 
ment is  0.45  meter  higher  than  the  left. 


652 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


The  stones  from  the  neighboring  quarries  were  soft  and  subject  to 
the  action  of  frosts,  currents,  and  particularly  the  tidal  wave  or 
bore,  a powerful  volume  of  water  preceding  the  flood  tide,  rushing 
up  the  river,  and  dashing  against  the  banks  with  great  violence ; 
this  has  undermined  and  sometimes  destroyed  the  original  walls. 

(140)  New  improvements. — Very  extensive  repairs,  or  rather  re- 
constructions, which  are  yet  going  on,  were  necessary,  which  bring 
up  the  total  cost  of  the  walls  to  the  sum  of  2S, 000, 000  francs  since 
the  beginning.  In  these  reconstructions  the  same  materials  are  em- 
ployed, but  to  protect  them  against  the  frost  and  the  bore  they  have 
been  covered  by  a facing  0.25  meter  thick.  To  defend  the  base 
against  being  undermined  at  the  places  where  the  bore  is  violent,  a 
concrete  apron  was  built,  3 meters  wide  and  0.40  meter  thick,  secured 
with  piling  and  planking  on  its  outer  edge. 

The  cost  of  the  walls  thus  reconstructed  amounts  to  250  francs  per 
running  meter.  These  reconstructions,  begun  in  1880,  are  rapidly 
progressing,  and  already  from  25  to  30  kilometers  are  finished  ; they 
were  indispensable  and  will  make  the  walls  last  a long  time. 

(141)  Alluvial  land. — Behind  the  training  walls,  and  in  parts  for- 
merly occupied  by  the  shifting  sands,  alluvial  meadows  have  been 
formed  to  an  extent  of  over  8,400  hectares  in  1880. 

They  are  divided  into  three  classes : land  made  over  to  the  river- 
side proprietors  ; land  belonging  to  the  state,  and  land  in  the  course 
of  formation. 

First.  The  state  made  over  2,613  hectares  to  the  river-side  proprie- 
tors and  received  an  indemnity  of  1,398,200  francs. 

Second.  An  area  of  3,710  hectares  yields  a profit  to  the  treasury 
every  year  by  rent  of  the  pasturage,  which  in  1878  amounted  to 
295,575  francs. 

Third.  An  area  of  2,077  hectares  is  in  the  course  of  formation. 

These  meadows  are  of  excellent  quality,  and  they  are  actually 
worth  4,000  francs  per  hectare.  When  all  the  alluvial  lands  now 
forming  are  definitely  constituted,  the  total  value  of  the  lands  thus 
reclaimed  will  be  33,600,000  francs.  Finally,,  it  should  be  under- 
stood that  these  calculations  only  include  the  lands  above  the  actual 
limit  of  the  training  walls,  and  that  the  influence  of  these  works 
extends  a long  distance  beyond  them  into  the  estuary. 

(142)  Results. — The  results  have  surpassed  all  anticipations.  The 
channel  has  become  fixed  and  deepened  between  the  walls  more  than 
2 meters,  so  that  vessels  of  2,000  tons  can  navigate  the  river,  the 
depth  being  at  low  tide  5.50  meters  and  at  high  tide  6.50  meters. 
The  charge  for  freight  between  Havre  and  Rouen  has  been  reduced 
one-half,  that  is,  to  5 francs  per  ton,  and  the  insurance  for  Rouen  is 
the  same  as  for  Havre.  The  traffic  has  consequently  increased  from 
500,000  tons  in  1860  to  1,600,000  tons  in  1888. 

(143)  The  effects  of  the  training  walls  have  been  confined  to  the 
channel  between  them,  but  their  deepening  influence  extends  little 


CIVIL  ENGINEERING,  ETC. 


653 


beyond  their  extremities.  The  estuary  channel  is  constantly  shift- 
ing. In  M.  Vautiers  report  he  traces  on  the  chart  of  the  estuary 
twelve  totally  different  locations  of  the  main  channel  beyond  the 
walls,  from  1874  to  1880. 

A prolongation  of  the  southern  bank  below  the  Risle  was  carried 
out  in  1870,  but  a proposed  prolongation  of  the  northern  bank  was 
refused,  and  the  works  finally  stopped,  for  fear  of  endangering  the 
approaches  to  Havre,  the  second  port  of  France,  by  the  silting  up 
of  the  estuary. 

(144)  The  following  account  by  Prof.  Vernon-Harcourt,  the  emi- 
nent hydraulic  engineer,  of  his  experiments  on  a model  of  the  lower 
Seine  created  great  interest  among  the  members  of  the  Congress  for 
Inland  Navigation  at  its  Paris  session  in  1889,  and  its  author  made, 
by  special  invitation,  a Report  on  the  Canalization  of  Rivers  and 
the  Different  Systems  of  Movable  Weirs. 

THE  PRINCIPLES  OF  TRAINING  RIVERS  THROUGH  TIDAL  ESTUARIES.* 

The  conditions  affecting  the  training  of  rivers  in  the  nontidal  portions  of  their 
course  by  jetties,  or  rubble  embankments  designated  as  training  walls,  are  well 
understood.  Training  walls  substitute  a straightened  uniform  channel  for  irregu- 
larities and  varying  widths,  improving  the  flow  of  the  current  and  rendering  it 
uniform,  so  that  scour  occurs  in  theshallow,  narrowed  portions,  and  more  uniformity 
of  depth  is  attained.  In  very  winding  rivers,  the  additional  precaution  has  to  be 
taken  of  somewhat  reducing  the  width  where  the  deepest  channel  shifts  over  from 
the  concave  bank  on  one  side  to  the  concave  bank  on  the  opposite  side  at  the  next 
bend  lower  down,  so  as  to  reduce  the  shoal  which  is  found  near  the  point  of  con- 
trary flexure  by  concentrating  the  current  at  this  place. 

The  training  of  the  outlets  of  sediment-bearing  rivers  into  tideless  seas  is  deter- 
mined by  the  same  principles;  for  a definite  discharge  is  directed  and  concentrated 
between  training  walls  or  piers,  so  as  to  scour  a channel  across  the  bar  formed,  in 
front  of  the  outlet,  by  the  accumulation  of  deposit  dropped  by  the  enfeebled  issuing 
current.  The  increased  velocity  of  the  current  through  the  contracted  outlet  car- 
ries the  silt  into  deeper  water,  where  it  is  either  borne  away  by  any  iittoral  current, 
or  again  forms  a bar,  after  a lapse  of  time  depending  on  the  depth,  which  can  be 
removed  by  an  extension  of  the  training  works. 

The  training  also  of  the  upper  part  of  the  tidal  portion  of  rivers  has  been  effected 
on  similar  principles  to  the  nontidal  portion,  with  satisfactory  results,  even  though 
the  problem  is,  in  this  case,  complicated  by  the  changes  in  the  direction  of  the  cur- 
rent, and  the  requisite  maintenance  of  the  tidal  capacity. 

In  the  lower  parts,  however,  of  tidal  rivers,  where  the  tidal  flow  predominates, 
it  is  difficult  to  determine  the  proper  width  for  a trained  channel,  which,  while  nar- 
row enough  to  secure  an  adequate  depth . should  not  very  materially  check  the  tidal 
flow  to  the  detriment  of  the  outlet.  Moreover,  where  the  estuary  is  large,  consid- 
erable doubt  may  exist  as  to  the  best  direction  for  the  training  walls  ; and  the  estab- 
lishment of  training  walls  in  a wide  estuary,  where  the  flood  tide  ischarged  with  silt, 
has  resulted  in  extensive  accretions,!  and  corresponding  reduction  of  tidal  capacity, 
by  the  concentration  of  the  tidal  flow  and  ebb  in  the  trained  channel,  and  a conse- 
quent enfeeblement  of  the  currents  at  the  sides,  favoring  deposit.  The  principles, 
indeed,  upon  which  the  training  of  tidal  rivers  should  be  based  are  in  a very  un- 

- * From  the  proceedings  of  the  Royal  Society,  Vol.  45,  p.  504. 

f Instit.  Civ.  Engin.  Proc.,  Vol.  84,  pp.  246  and  295,  and  Pis.  4 and  5. 


654 


UNIVERSAL  EXPOSITION-  OF  1889  AT  PARIS. 


defined  and  unsatisfactory  condition,  as  exemplified  by  the  conflicting  opinions  of 
engineers  whenever  important  training  works  through  estuaries  are  proposed,  as 
exhibited  with  reference  to  the  schemes  for  training  works  in  the  upper  estuary  of 
the  Mersey,*  for  which  the.  Manchester  Ship  Canal  promoters  sought  powers  in  1888 
and  1884,  and  as  at  present  exist  about  the  extension  of  the  training  works  in  the 
Kibble  estuary.  (■  This  is  due  to  the  various  conditions  involved,  which  differ  more 
or  less  in  each  case,  and  thus  render  it  difficult  to  lay  down  general  rules  for  guid- 
ance from  arguments  based  on  analogy.  One  of  the  most  important  considerations 
is  the  form  of  the  estuary  ; and  in  this  respect  no  two  estuaries  are  alike,  as  their 
form  is  the  result  of  complex  geological  and  hydrological  conditions ; and  it  suffices 
to  contrast  the  Mersey  and  the  Kibble,  the  Dee  and  the  Tay,  the  Clyde  and  the  Tees, 
the  Seine  and  the  Loire,  to  indicate  the  varieties  of  forms  which  may  have  to  be 
dealt  with.  Other  circumstances  affecting  the  problem  are  the  rise  of  tide,  the  tidal 
capacity  and  general  depth,  the  fresh-water  discharge,  the  silt  introduced  by  the 
flood  tide  or  brought  down  by  the  river,  the  condition  of  the  sea  bottom  in  front  of 
the  mouth,  and  the  direction  in  which  the  tidal  current  enters  the  estuary.  The 
positions  also  of  ports  established  at  the  sides  of  estuaries  require  special  considera- 
tion in  determining  the  proper  line  for  a trained  channel.  These  numerous  and 
variable  conditions  have  often  led  engineers  to  enunciate  the  opinion  that  each  river 
must  be  considered  independently  by  itself.  This  view,  however,  if  strictly  ad- 
hered to,  by  excluding  the  experience  derived  from  previous  works,  would  prevent 
any  progress  in  the  determination  of  general  principles  for  the  improvement  of 
navigation  channels  through  estuaries;  each  training  work  would  form  an  inde- 
pendent scheme,  based  upon  no  previous  experience,  and  might  or  might  not  pro- 
duce the  results  anticipated  by  its  designer.  Unfortunately  also  it  is  impossible  to 
proceed  with  training  works  by  the  method  of  trial  and  error  ; for  besides  the  cost 
of  modifying  the  lines  of  training  walls,  if  the  desired  results  are  not  produced, 
these  works  generally  effect  such  extensive  changes  in  an  estuary  that  it  would  be 
impracticable  to  restore  the  original  conditions,  or  to  modify  materially  the  altered 
position. 

(145)  It  might  be  possible  to  deduce  general  rules  for  training  works  from  a care- 
ful consideration  of  a variety  of  types  of  estuaries,  especially  those  in  which  train- 
ing works  have  been  carried  out ; and  I have  commenced  an  investigation  of  this 
kind.  This  method  of  inquiry,  however,  requires  a variety  of  data  which  it  is 
difficult  to  obtain  for  most  estuaries,  and  must  depend  upon  a careful  estimate  of 
the  relative  influence  of  each  of  the  variable  conditions,  and  a train  of  reasoning 
from  analogy  which  might  not  be  accepted  by  engineers  as  conclusive.  Accord- 
ingly, it  would  be  of  the  very  highest  value  to  river  engineers,  and  of  considerable 
interest  from  a scientific  point  of  view,  if  a method  of  investigation  could  be  de- 
vised which  might  be  applied  to  the  special  conditions  of  any  estuary,  and  the 
results  of  any  scheme  of  training  works  determined  approximately  beforehand  in 
a manner  which  could  be  relied  upon  from  the  fact  of  their  depending  on  an  assimi- 
lation to  the  actual  conditions  of  the  case  investigated,  and  noton  arguments  based 
upon  the  effects  of  similar  works  under  more  or  less  different  conditions.  The  fol- 
lowing description  is  therefore  given  of  the  results  of  investigations,  carried  on  at 
intervals  during  more  than  two  .years,  with  reference  to  the  proposed  extensions  of 
the  training  works  in  the  Seine  estuary,  which  appear  to  afford  a fair  assurance 
that  a similar  method,  applied  to  any  estuary  would  indicate  the  effect  of  any 
scheme  of  training  works,  provided  the  special  conditions  of  the  estuary  were 
known. 

* Evidence  before  select  committee  of  Lords  and  Commons  on  the  Manchester 
ship  canal  bills,  sessions  1883  and  1884,  and  Instit.  Civ.  Engiu.  Proc.,  Yol.  84,  p. 
309,  Fig.  7. 

+ Instit.  Civ.  Engin.  Proc.,  Vol.  84,  p.  260,  Fig.  1. 


CIVIL  ENGINEERING,  ETC. 


655 


INVESTIGATIONS  ABOUT  THE  SEINE  ESTUARY. 

(146)  The  training  works  in  the  lower  portion  of  the  tidal  Seine,  commenced  in 
1848,  had  reached  Berville  in  1870,  when  the  works  were  stopped,  in  the  interests  of 
the  port  of  Havre,  on  account  of  the  large  unexpected  accretions  which  were  tak- 
ing place  behind  the  training  walls,  and  at  the  sides  of  the  wide  estuary  below 
them.*  The  original  scheme,  proposed  in  1845  by  M.  Bouniceau,t  comprised  the 
extension  of  the  trained  channel  to  Honfleur  on  the  southern  side  of  the  estuarv, 
and  the  prolongation  of  one  or  both  of  the  training  walls  towards  Havre  at  the 
northwestern  extremity  of  the  estuary,  as  in  any  scheme  the  interests  of  both 
these  ports,  on  opposite  sides  of  the  estuary,  have  to  be  considered.  The  works  are 
acknowledged  to  be  incomplete ; and  great  interest  has  been  evinced,  particularly 
within  the  last  few  years,  in  the  question  of  their  extension,  so  that  the  shifting 
channel  between  Berville  and  the  sea  may  be  trained  and  deepened,  and  the  access 
to  Honfleur  improved,  without  endangering  the  approaches  to  Havre.  The  objects 
desired  are  distinctly  defined,  but  the  means  for  attaining  them  have  formed  the 
subject  of  such  a variety  of  schemes  that  hardly  any  part  of  the  estuary  below 
Berville  has  not  been  traversed  by  some  proposed  trained  channel,  except  the  por- 
tion lying  north  of  a line  between  Hoc  and  Tancarville  points,  which  is  too  far 
removed  from  Honfleur  to  be  admissible  for  any  scheme.  Altogether,  including 
distinct  modifications,  fourteen  schemes  have  been  published  in  France  within  my 
knowledge,  seven  of  them  having  appeared  within  the  last  five  years.  The  schemes 
also  exhibit  great  varieties  in  their  general  design  } (Figs.  99,  101,  102,  103,  and  105), 
illustrating  very  forcibly  the  great  uncertainty  which  exists,  even  in  a special  case 
where  the  conditions  have  been  long  studied,  as  to  the  principles  which  should  be 
followed  in  designing  training  works.  It  is  evident  that  no  reasoning  from  analogy 
could  prevail  among  such  very  conflicting  views;  and  having  had  the  subject  under 
consideration  for  a long  time,  the  idea  occurred  to  me  in  August,  1886,  of  attempt- 
ing the  solution  of  this  very  difficult  problem  by  an  experimental  method,  which 
might  also  throw  light  upon  general  principles  for  guidance  in  training  rivers 
through  estuaries.  The  estuary  of  the  Seine  is  in  some  respects  peculiarly  well 
adapted  for  such  an  investigation,  for  old  charts  exhibit  the  state  of  the  river  before 
the  training  works  were  commenced,  and  recent  charts  indicate  the  changes  which 
the  training  walls  have  produced,  while  the  various  designs  for  the  completion  of  the 
works,  proposed  by  experienced  engineers,  afford  an  intereresting  basis  for  exper- 
imental inquiries  into  the  principles  of  training  works  in  estuaries.  If,  in  the  first 
place,  it  should  be  possible  to  reproduce  in  a model  the  shifting  channels  of  the 
Seine  estuary  as  they  formerly  existed,  and  next,  after  inserting  the  training  walls 
in  the  model  as  they  now  exist  in  the  estuary,  the  effects  produced  by  these  works 
could  lie  reproduced  on  a small  scale,  it  appeared  reasonable  to  assume  that  the 
introduction,  successively,  in  the  model  of  the  various  lines  proposed  for  the  exten- 
sion of  the  training  walls  would  produce  results  in  the  model  fairly  resembling  the 
effects  which  the  works,  if  carried  out,  would  actually  produce. 

(147)  When  the  third  Manchester  ship  canal  bill  was  being  considered  by  Parlia 
ment,  in  1885,  Prof.  Oborne  Reynolds  constructed  a working  model  of  the  por- 
tion of  the  Mersey  estuary  above  Liverpool  on  behalf  of  the  promoters  of  the  canal, 
with  the  object  of  showing  that  no  changes  would  be  produced  in  the  main  chan- 
nels of  the  estuary  by  the  canal  works,  which  have  been  designed  to  modify  very 
slightly  the  line  of  the  Chesire  shore  above  Eastham.  This  model  was,  I believe, 
the  first  experimental  investigation  on  an  estuary  by  artificially  producing  the  tidal 

*Instit.  Civ.  Engin.  Proc.,  Vol.  84,  p.  241,  and  Pis.  4 and  5. 

, + Etude  sur  la  Navigation  des  Rivieres  a Marees,  M.  Bouniceau,  p.  152,  PI.  2. 

Jlnstit.  Civ.  Engin.  Proc.,  vol.  84,  p.  247,  and  PI.  4,  Fig.  9. 


G56 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


action  of  flood  and  ebb  on  a small  scale,  and  Prof.  Reynolds’s  experiment  showed 
that  a remarkably  close  resemblance  to  the  main  tidal  channels  in  the  inner  estuary 
could  be  produced  on  a small  scale. 

As  the  Mersey  model  did  not  extend  into  Liverpool  Bay,  the  tidal  action  produced 
was  very  definitely  directed  along  the  confined  channel  representing  the  “ Narrows” 
between  Liverpool  and  Birkenhead;  and  this  tidal  flow  was  not  perceptibly  influ- 
enced by  the  relatively  very  small  fresh- water  discharge.  In  the  Seine,  however, 
there  is  no  narrow  inlet  channel  to  adjust  exactly  the  set  of  the  flood  tide  into  the 
estuary ; and  the  fresh-water  discharge  of  the  Seine,  with  a basin  about  eighteen 
times  larger  than  the  Mersey  basin,  forms  an  important  factor  in  the  result.  The 
tide  in  a model  of  the  Seine  has  to  he  produced  in  the  open  bay  outside  the  estuary 
at  a suitable  angle  which  had  to  be  determined  ; and  it  was  essential  for  the  success 
of  the  Seine  experiments  that  accretion  should  be  produced  in  the  model  of  the 
Seine  estuary  under  certain  circumstances,  which  was  a condition  which  did  not 
enter  into  the  Mersey  problem.  Accordingly,  the  very  interesting  and  valuable  re- 
sults obtained  by  Prof.  Reynolds,  in  his  model  of  the  Mersey,  could  afford  no 
assurance  that  experiments  involving  essentially  different  and  novel  conditions 
would  lead  to  any  satisfactory  results.  I therefore  restricted  the  requirements  for 
my  experiments  within  the  smallest  possible  limits,  and  contented  myself  with  the 
simplest  means,  and  the  limited  space  available  in  my  office  at  Westminster. 

(148)  Description  of  model  of  the  Seine  estuary. — The  model  representing  the 
tidal  portion  of  the  river  Seine  and  the  adjacent  coast  of  Calvados,  extending  from 
Martot,  the  lowest  weir  on  the  Seine,  down  to  about  Dives,  to  the  southwest  of  Trou- 
ville,  was  molded  in  Portland  cement  by  my  assistant.  Mr.  Edward  Blundell,  to  the 
scales  of  horizontal  and  ?ki3  vertical.  The  first  is  the  scale  of  some  of  the 
more  recent  published  charts  of  the  Seine — and  even  at  that  scale  the  model  is  nearly 
9 feet  long — whilst  I made  the  vertical  scale  one  hundred  times  the  horizontal,  as 
the  fall  of  the  bed  of  the  tidal  Seine  is  very  slight,  and  the  rise  of  spring  tides  at 
the  mouth,  being  23  feet  7 inches,  amounted  to  an  elevation  of  the  water  in  the 
model  of  only  0.71  inch.  There  are  two  banks  at  the  mouth  of  the  estuary,  between 
Havre  and  Villerville  Point,  known  as  the  Amfard  and  Ratier  banks,  which  emerge 
between  half  tide  and  low  water,  and  divide  the  entrance  to  the  estuary  into  three 
channels.  Through  all  the  changes  in  the  navigable  channel  at  the  outlet,  these 
banks  always  appear  in  some  form  or  other  in  the  low-water  charts,  either  connected 
with  the  sand  banks  inside  the  estuary  or  detached.  On  examining  the  large  chart 
drawn  from  the  survey  made  by  M.  Germain  in  1880,  I found  that  rock  and  gravel 
cropped  up  to  the  surface  over  a certain  area  on  these  banks,  and  accordingly  I in- 
troduced solid  mounds  at  these  places  to  represent  the  hard  portions  of  the  Amfard 
and  Ratier  banks,  which  are  permanent  features  in  theestuary.  As  a rocky  bottom 
is  found  near  Havre,  and  also  at  Villerville  Point  on  the  opposite  side  of  the  outlet, 
Amfard  and  Ratier  banks  are  doubtless  the  remains  of  a rocky  barrier  which  in 
remote  ages  stretched  right  across  the  present  mouth  of  the  river.  Where  the  rocky 
bottom  lies  bare,  near  Havre  and  Villervile,  the  model  was  molded  to  the  exact 
depths  shown  on  the  chart  of  1880:  but  in  other  places  the  cement  bottom  was 
merely  kept  well  below  the  greatest  depth  the  channel  had  attained  at  each  place, 
whilst  the  actual  bed  of  the  estuary  in  the  model  was  formed  by  the  flow  of  water 
over  a layer  of  sand. 

(149)  Arrangements  for  tidal  and  fresh-water  flow. — The  mouth  of  the  Seine  estuary 
faces  west,  but  the  tidal  wave  comes  in  from  the  northwest,  and  the  earliest  and 
strongest  flood  tide  flows  through  the  northern  channel  between  Havre  and  the 
Amfard  bank  ; whilst  the  influx  through  the  southern  Villerville  channel  occurs 
later,  and  is  stronger  toward  high  water.  Accordingly,  the  tidal  flow  had  to  be  in- 
troduced from  a northerly  direction,  at  an  angle  to  the  mouth  of  the  estuary  ; and 
the  line  of  junction  of  the  hinged  tray,  producing  the  tidal  rise  and  fall,  was  made 


CIVIL  ENGINEERING,  ETC. 


657 


at  an  angle  of  about  50°  to  a line  running  from  east  to  west  in  the  model,  so  that  the 
tidal  flow  approached  the  estuary  from  a point  only  about  5°  to  the  west  of  north- 
west. The  tray  was  made  of  zinc,  inclosed  by  strips  on  three  sides  to  the  height  of 
the  sides  of  the  estuary  ; and  it  was  hinged  to  the  model,  at  its  open  end,  by  a strip 
of  india-rubber  sheeting  along  the  bottom  and  sides,  so  as  to  make  a water-tight 
joint  with  sufficient  play  at  the  sides  to  admit  of  the  tray  being  tipped  up  and  down 
from  its  outer  end.  The  rise  and  fall  of  the  tray  was  effected  by  the  screw  of  a 
letter  press,  from  which  the  lower  portion  had  been  detached,  by  raising  and  lower- 
ing the  upper  plate  of  the  press,  half  of  which  was  inserted  under  the  tray.  After 
the  requisite  amount  of  sand  had  been  introduced  to  raise  the  bottom  to  the  aver- 
age level,  the  model  was  Filled  with  just  enough  water  for  the  surface  of  the  water 
to  represent  low  water  of  spring  tides  when  the  tray  was  down  and  the  screw  at  its 
lowest  limit ; and  the  tray  was  madeof  such  a size  that,  when  the  screw  was  raised 
to  its  full  extent,  the  water  in  the  model  was  raised,  by  the  tipping  of  the  tray,  to 
the  level  representing  high  water  of  spring  tides.  The  water  representing  the  fresh- 
water discharge  of  the  Seine  was  admitted  into  the  upper  end  of  the  model  from 
a tap  in  a small  tin  cistern  ; and  the  efflux  of  a similar  quantity  of  water  was  pro- 
vided for  at  the  lower  extremity  of  the  estuary,  on  its  northern  side  near  the  tray, 
by  a cock  with  a larger  orifice  placed  at  such  a level  as  to  allow  the  water  to  How 
out  into  a second  cistern,  of  similar  size,  during  the  higher  half  of  the  tide. 

(150)  First  results  of  working  the  model. — The  construction  of  the  model  wascom- 
menced  in  October,  1886,  and  its  working  was  commenced  in  November.  Though 
the  Portland  cement  was  convenient  for  molding  in  a small  space  and  in  the  absence 
of  appliances,  it  did  not  prove  satisfactory  for  retaining  water  at  first.  The  model 
was  purposly  made  in  two  halves,  and  the  straight  joint  was  subsequently  made 
water-tight;  but,  nevertheless,  era 'ks  occurred  at  various  places  through  which  the 
water  leaked,  and  they  had  to  be  repaired  as  they  appeared  ; and  the  bottom  of  the 
model  was  eventually  coated  with  thick  varnish,  and  after  a time  the  leaks  ceased. 
The  flexible  india-rubber  hinge,  from  which  I had  anticipated  some  trouble,  leaked 
very  little  from  the  beginning,  and  on  being  fitted  with  greater  care  in  introducing 
a tray  of  somewat  different  form,  no  leakage  occurred. 

Silver  sand  was  used  in  the  first  instance  for  forming  the  bed  of  the  estuary'. 
From  the  outset  the  bore  at  Caudehec  indicated  by  a sudden  rise  of  the  water,  and 
the  reverse  current  just  before  high  water  near  Havre,  called  the  “ verhaide ,”  were 
very  well  marked.  The  verhaule  is  evidently  a sort  of  back  eddy,  on  the  northern 
shore,  occasioned  by  the  influx  of  the  tide,  and  by  the  final  filling  of  the  estuary 
from  the  southern  channel ; whilst  the  bore  appears  to  result  from  the  concentra- 
tion of  the  tidal  rise  by  the,  sudden  contraction  of  the  estuary  above  Quillebeuf. 
The  period  given  to  each  tide  in  working  was  about  twenty-five  seconds,  which  ap- 
peared fairly  to  reproduce  the  conditions  of  the  estuary.*  After  the  model  had  been 
worked  fora  little  time,  the  channels  near  Quillebeuf  assumed  lines  resembling  those 
which  previously  existed,  and  a small  channel  appeared  on  the  northern  shore,  by 
Harfleur  and  Hoc  Point,  which  is  clearly  defined  in  the  chart  of  1834.  The  main 
channel  also  shifted  about  in  the  estuary  and  tended  to  break  up  into  two  or  three 
shallow  channels  near  the  meridian  of  Berville,  where  the  influencesof  the  flood  and 
ebb  tides  were  nearly  balanced.  The  model,  accordingly,  fairly  reproduced  the  condi- 
tions of  the  actual  estuary  previous  to  the  commencement  of  the  training  walls, 
though  the  channel  in  the  estuary  diil  not  attain  the  depth,  as  represented  by  the 
proportionately  large  vertical  scale,  which  the  old  channels  possessed,  owing,  doubt- 
less, to  the  comparatively  small  scouring  influence  which  the  minute  currents  in 

* According  to  the  formula  in  the  paper  by  Prof.  O.  Reynoldson  his  Mersey  model, 
read  at  the  Frankfort  Congress  in  August,  1888,  the  tidal  period  would  be  nearly 
twenty-three  seconds. 

H.  Ex.  410 — VOL  III 


42 


658 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


the  model  possess.  The  sand,  in  fact,  can  not  be  reduced  to  a fineness  corresponding 
to  the  scale  of  the  model,  whilst  the  friction  on  the  bed  is  not  diminished  equiva- 
lently to  the  reduction  in  volume  of  the  current.  Silver  sand  has  been  used  on 
account  of  its  being  readily  obtained,  its  purity,  and  absence  of  cohesion,  as  it  was 
hoped  that  the  water  by  percolating  freely  through  it  would  more  readily  shift  it. 
A film,  however,  seemed  by  degrees  to  form  over  its  surface,  reducing  considerably 
its  mobility,  and  as  the  action  of  the  water  on  it  consisted  merely  in  rolling  the 
particles  along  the  bottom,  this  sand  did  not  prove  satisfactory  for  producing  the 
requisite  changes  when  the  training  walls  were  inserted  in  the  model.  It  became, 
therefore,  essential  to  search  for  a substance  which  the  water  could  to  some  extent 
carry  in  suspension  for  a short  period. 

(151)  Trial  of  various  substances  for  forming  the  bed  of  the  estuary. — Some  sub- 
stance was  required,  not  necessarily  sand,  insoluble  in  water,  easily  scoured,  and 
therefore  not  pasty  or  sticky,  and  sufficiently  tine  or  light  to  be  carried  in  suspen- 
sion  to  some  extent  by  the  currents  in  the  model,  and  not  merely  rolled  along  the 
bottom  like  the  silver  sand.  A variety  of  substances  of  low  specific  gravity,  and  in 
powdered  form,  were  accordingly  tried  in  succession  during  the  first  half  of  1887. 
Pumice  in  powder  proved  too  sticky,  and  flour  of  sulphur  was  too  greasy  to  be  easily 
immersed  in  water.  Pounded  coke  was  too  dirty  to  be  suitable,  and  particles  of  it 
floated.  Violet  powder  became  too  pasty  in  water,  and  fuller’s  earth  and  lupin  seed 
exhibited  similar  defects.  The  grains  of  coffee  grounds  were  too  large  in  water, 
and  moved  up  and  down  in  the  currents  too  readily,  whilst  fine  sawdust  from  box- 
wood and  lignum  vitae  swelled  in  water  and  was  carried  along  so  very  easily  by  the 
stream  that  no  definite  channels  were  formed  in  it.  The  powder  obtained  from 
Bath  brick,  which  was  experimented  upon  for  some  time  in  the  model,  both  with- 
out and  with  training  walls,  yielded  more  satisfactory  results,  as.  besides  affording 
shifting  channels  like  the  silver  sand,  it  accumulated  at  the  sides  of  the  estuary 
when  the  training  walls  were  introduced  in  the  model.  It,  however,  gradually  be- 
came too  compact,  so  that  the  current  could  no  longer  produce  much  effect  on  it; 
but  as  it  is  probable  that  some  sticky  material  is  used  in  the  manufacture  of  Bath 
bricks,  it  is  quite  possible  that  if  I had  succeeded  in  my  endeavor  to  obtain  the  silt 
of  the  river  Parrot,  from  which  the  bricks  are  made,  in  its  natural  state,  the  mate- 
rial might  have  proved  more  subject  to  scouring  influence. 

At  last,  in  July,  1887,  I found  a fine  sand,  on  Chobham  Common,  belonging  to 
the  Bagshot  beds,  with  a small  admixture  of  peat.  This  sand,  besides  containing 
some  very  fine  particles,  was  perfectly  clean,  so  that  water  readily  percolated 
through  it;  and  it  accordingly  combined  the  advantages  possessed  by  silver  sand 
with  a considerably  greater  fineness. 

(152)  Results  of  working  model  with  Bagshot  sand. — The  bed  of  the  estuary  hav- 
ing been  formed  with  the  sand  obtained  from  Chobham  Common,  after  the  model 
had  been  worked  for  some  time,  the  channels  assumed  a form  very  closely  resem- 
bling the  chart  of  the  Seine  estuary  of  1834.*  Accordingly,  the  first  stage  of  the 
investigation  was  duly  accomplished  by  the  reproduction  of  a former  state  of  the 
estuary  in  the  model,  with  the  single  exception  of  a decidedly  smaller  depth  in  the 
channels,  except  in  places  where  the  scour  was  considerable;  which  is  readily  ac- 
counted for  by  the  circumstances  of  the  case.  It  is  probable  that  with  a larger 
model,  and  especially  if  the  bed  was  not  so  nearly  level  as  in  the  Seine,  the  depth 
would  approach  nearer  to  the  proper  distorted  proportion  as  compared  with  the 
width. 

The  close  correspondence  of  the  channels  in  the  model  with  an  actual  state  of 
the  estuary  in  its  natural  condition,  confirms,  in  a considerably  more  complicated 
case,  the  results  previously  achieved  by  Prof.  Reynolds  with  reference  to  the  upper 
estuary  of  the  Mersey,  and  affords  a fair  certainty  that,  with  adequate  data,  the 
natural  condition  of  any  estuary  could  be  reproduced  on  a small  scale  in  a model. 

*Instit.  Civ.  Engin.  Proc.,  vol.  84,  Plate  5,  fig.  1. 


CIVIL  ENGINEERING,  ETC. 


059 


Introduction  of  the  existing  training  walls  in  the  model. — The  second  stage  of 
the  investigation  consisted  in  the  introduction  of  training  walls  into  the  model, 
corresponding  in  position  to  the  actual  training  walls  established  in  the  estuary 
down  to  Berville.  These  walls,  formed  with  strips  of  tin,  cut  to  the  corresponding 
heights  at  the  different  places,  and  bent  to  the  proper  lines,  were  gradually  inserted 
in  sections ; and  the  model  was  worked  between  each  addition,  to  conform,  as  far 
as  practicable,  to  the  actual  conditions.  The  fine  particles  of  the  sand  accreted 
behind  the  training  walls,  and  the  channel  between  the  walls  was  scoured  out, 
corresponding  precisely  to  the  changes  which  have  actually  occurred  in  the  estuary 
of  the  Seine.  The  foreshores  at  the  back  of  the  training  walls  were  raised  up  in 
some  parts  to  high-water  level,  whilst  in  other  places  the  accumulation  was  some- 
what retarded  by  the  slight  recoil  of  the  water  from  the  vertical  sides  of  the  model, 
and  by  the  wash  over  the  vertical  training  walls,  these  forms  being  necessitated  by 
the  great  distortion  of  the  vertical  scale  of  the  model.  On  the  whole,  however, 
the  accretion  and  scour  in  the  model  correspond  very  fairly  to  the  results  produced 
by  the  existing  training  walls  in  the  estuary.  Tiie  accretion,  moreover,  in  the 
model,  extended  beyond  the  training  walls  on  each  side,  down  to  Hoc  Point  on  the 
right  bank,  obliterating  the  inshore  channel  close  to  Harfleur,  which  had  been  repro- 
duced in  the  model,  and  down  to  Ilonfleur  on  the  left  bank,  corresponding  in  these 
respects  also  to  the  actual  changes  in  the  estuary.*  The  main  channel  also,  beyond 
the  ends  of  the  training  walls,  was  comparatively  shallow,  and  was  unstable,  repro- 
ducing the  existing  conditions  in  the  estuary. 

The  experiments  relating  to  this  stage  extended  over  a year  and  a half,  taking, 
up  all  the  time  that  could  be  spared  to  them  by  myself  and  my  assistant  during 
that  period ; they  formed  the  turning  point  of  the  investigation,  and  have  the  inter- 
est of  being,  as  far  as  I am  aware,  the  first  attempt  at  putting  training  walls  in  a 
model,  and  obtaining  the  resulting  accretion  on  a small  scale.  Without  the  accom- 
plishment of  this  stage,  it  would  have  been  useless  to  continue  the  investigation; 
and  its  satisfactory  attainment  proved  so  difficult  in  actual  practice,  that  for  a long 
time  it  seemed  probable  that  the  attempt  must  be  abandoned. 

(153)  Application  of  system  to  ascertain  the  probable  effects  of  any  training 
works. — As  the  first  and  second  steps  in  the  investigation,  by  the  aid  of  the  model, 
had  furnished  results  which  corresponded  very  fairly  with  the  actual  states  of  the 
estuary  of  the  Seine  before  and  after  the  execution  of  the  training  works,  the  final 
stage  of  the  investigation,  for  ascertaining  the  probable  results  of  any  extensions 
of  the  training  walls,  could  be  reasonably  entered  upon.  In  selecting  the  lines  of 
training  walls  to  l>e  experimented  on,  it  appeared  expedient  to  adopt  those  which 
have  been  designed,  after  careful  study,  by  experienced  engineers,  both  on  account 
of  the  results  from  these  being  far  more  interesting  than  those  of  a variety  of  theo- 
retical schemes,  and  also  in  the  hope  that  some  assistance  might  thereby  be  ren- 
dered to  French  engineers  in  the  prosecution  of  this  important  work.  Moreover, 
the  schemes  exhibit  sufficient  variety  to  admit  of  their  being  taken  as  types  of 
schemes  for  throwing  light  upon  the  principles  on  which  training  works  should  be 
designed  in  estuaries.  Accordingly,  the  third  stage  in  the  investigation  consisted 
in  extending  the  training  walls  in  the  model,  in  accordance  with  the  lines  of  some 
of  the  schemes  proposed ; and,  after  working  the  model  for  some  time  with  each 
of  the  extensions  successively,  the  several  results  were  recorded,  as  shown  in  figs. 
1)9-106.  The  lines  of  training  walls  experimented  on  in  the  model  were  taken,  with 
one  exception,  from  five  out  of  the  seven  most  recent  schemes  proposed,  as  these 
five  schemes  are,  I believe,  the  only  ones  which  are  still  put  forward  for  adoption. 
The  lines  shown  on  Fig.  107,  represent  merely  a theoretical  arrangement  of  train- 
ing walls,  inserted  for  a final  experiment  in  the  model,  to  ascertain  the  effect  of 

*Instit.  Civ.  Engin.  Proc.,vol.  84;  compare  plate  5,  fig.  1,  and  plate  4,  fig.  1. 


660 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


the  most  gradual  enlargement  of  the  trained  channel  which  the  physical  conditions 
of  the  estuary  would  have  admitted  of  at  the  outset,  whilst  maintaining  the  full 
width  at  the  mouth. 

(154)  Scheme  A. — The  first  arrangement  of  extended  training  walls  introduced 
into  the  model  taken  from  a scheme,  some  of  the  main  features  of  which  were  pro- 
posed in  an  earlier  scheme  in  1859,*  and  which  was  put  forward  in  an  amended 
form  in  1886. f The  design,  as  inserted  in  the  model,  consisted  of  an  extension  of 
the  parallel  training  walls  from  Berville  down  to  Ilonfleur,  and  the  formation  of  a 
breakwater  across  the  outlet,  from  Villerville  Point,  on  the  southern  shore  of  the 
estuary,  out  to  the  Amfard  bank,  thus  restricting  the  mouth  to  the  channel  between 
Amfard  bank  and  Havre.  The  lines  of  these  works  were  formed  in  the  model  with 
strips  of  tin.  as  shown  on  Fig.  99;  the  northern  training  wall  was  kept  low, 
and  the  southern  wall  was  raised  to  the  level  representing  high  water  of  neap  tides; 
whilst  the  strip  representing  the  breakwater  was  raised  above  the  highest  tide 
level,  thus  forcing  all  the  flood  and  ebb  water  to  pass  through  the  Havre  Channel. 
The  results  obtained  in  the  model  with  these  arrangements,  after  working  it  for 
about  six  thousand  tides,  are  indicated  on  the  first  chart  (Fig.  99).  The  channel  be- 
tween the  prolonged  training  walls  had  a fair  depth  throughout,  partly  owing  to 
the  concentration  of  the  fresh-water  discharge  between  the  walls,  and  partly  from 
the  retention  of  some  additional  water  in  the  channel  at  low  water,  by  the  hindrance 
to  its  outflow  offered  by  a sandbank  which  formed  in  front  of  the  ends  of  the  train- 
ing walls.  A deep  hole  was  soon  scoured  out  in  the  narrowed  outlet  by  the  rapid 
flow  of  the  water  filling  and  emptying  the  estuary  at  every  tide.  The  absence, 
however,  of  connection  between  the  direction  of  the  flood  tide  current  through  the 
outlet  and  the  ebbing  current  from  the  trained  channel,  aided  by  the  accretion  of 
sand  in  the  sheltered  recess  behind  the  breakwater,  led  eventually  to  the  formation 
of  two  almost  rectangular  bends  in  the  channel,  one  just  beyond  the  training  walls 
and  the  other  near  Hoc  Point,  in  the  model.  This  tortuous  channel,  moreover, 
was  shallow,  except  at  the  bends  and  the  outlet,  and  a bar  was  formed  a short  dis- 
tance beyond  the  outlet.  The  contraction  of  the  mouth  of  the  estuary  by  the 
breakwater  interfered  so  much  with  the  influx  of  the  tide  into  the  estuary  as  to 
render  it  impossible  to  raise  the  tide  inside  to  its  previous  height,  and  the  reduction 
in  height  of  tire  tide  was  clearly  marked  at  Tancarville  Point  in  the  model.  Sedi- 
ment accumulated  in  the  estuary  beyond  the  trained  channel,  being  brought  in 
by  the  rapid  flood  current,  and  not  readily  removed  by  the  ebb,  except  in  the  trained 
channel  and  near  the  outlet;  and  this  accretion,  by  diminishing  the  tidal  capacity, 
gradually  reduced  the  current  through  the  outlet,  and  consequently  the  depth  of 
the  outlet  channel.  A considerable  accumulation  of  sand  took  place  outside  the 
breakwater,  along  the  southern  seacoast,  so  that  the  bank  opposite  Trouville  in  the 
model  was  connected  with  the  shore,  and  the  foreshore  advanced  towards  the  end 
of  the  breakwater  (Fig.  99). 

(155)  Scheme  B. — The  second  arrangement  of  training  walls  inserted  in  the  model 
below  Berville.  was  taken  from  a scheme  proposed  in  1888.  representing  a modifica- 
tion by  another  engineer  of  the  design  from  which  Scheme  A was  copied. | It 
comprised  the  retention  of  the  breakwater  from  Villerville  Point  to  the  Amfard 
bank,  the  most  essential  feature  in  Scheme  A;  but  the  extension  of  the  northern 
training  wall  was  dispensed  with,  whilst  the  southern  training  wall  was  prolonged, 

*“  La  Seine  comtne  Voie  de  Communication  Maritime  et  Fluviale,”  J.  de  Coene, 
1883,  p.  11,  and  plate  7. 

f“  Projet  desTravaux  a faire  a la’Embouchure  de  la  Seine.”  L.  Partiot,  Paris,  1886. 

| Memoires  de  la  Societe  des  Ingenieurs  Civils,  Mars,  1888,  Paris,  pp.  257  and  273, 
and  PI  .162,  Fig.  2. 


CIVIL  ENGINEERING,  ETC.  661 

in  a continuous  curve,  from  Berville  to  Honfleur  (Fig.  100),  and  eventually  to  the 
Amfard  bank,  connecting  it  there  with  the  extremity  of  the  breakwater  (Fig.  101.) 


TR0UVH.Lt 


Fig.  99.— Scheme  A.* 


A slight  widening  out  of  the  existing  trained  channel  by  an  alteration  of  the  end 
portion  of  the  northern  training  wall,  completed  the  arrangement  of  the  model. 


'uLUVmi 


Fig.  100— Scheme  R. 


The  results  obtained  by  inserting  the  training  wall  down  to  Honfleur,  and  then 
working  the  model  for  about  3,500  tides,  are  shown  in  Fig.  100;  and  those  obtained 


Fig.  01— Scheme  B2. 


after  the  prolongation  of  the  southern  training  wall  to  the  breakwater,  and  work- 
ing the  model  for  about  3,700  tides,  are  shown  in  Fig.  101.  The  channel  followed 
pretty  nearly  the  concave  line  of  the  prolonged  southern  training  wall,  between 


1 1 £P/i  ILE 


"The  existing  training  walls  stop  at  Berville. 


662 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


Berville  and  Honfleur. in  the  model,  except  near  Berville;  but  the  depth  of  water 
was  less  regular  than  in  the  previous  experiment,  owing  to  the  diminished  concen- 
tration of  the  ebb  from  the  absence  of  the  northern  training  wall.  The  channel 
between  Honfleur  and  Ainfard  was  tortuous  as  before,  but  its  direction  was  differ- 
ent. The  deej)  hole  at  the  outlet,  the  bar  beyond,  and  the  advance  of  the  southern 
foreshore  beyond  the  breakwater,  reappeared  again  with  very  similar  features  to 
those  in  the  first  scheme,  except  that  the  sandbank  did  not  quite  reach  the  outside 
face  of  the  breakwater  at  low  water.  (Compare  Fig.  100  with  Fig.  99.) 

(156)  The  results  which  followed  from  working  the  model  with  the  southern 
training  wall  prolonged  to  Amfard  are  shown  in  Fig.  101.  The  main  alteration 
from  the  former  experiment  naturally  occurred  between  Honfleur  and  Amfard  in 
the  model,  a continuous  channel  being  formed  along  the  new  piece  of  concave 
training  wall;  whilst  the  general  depth  inside  the  estuary  was  improved  as  far  as 
the  meridian  of  Hoc  Point.  The  channel,  however,  above  Honfleur  was  not  im- 
proved, owing  apparently  to  the  want  of  uniformity  between  the  directions  of  the 
flood  and  ebh  currents  in  the  model.  The  other  features  remained  very  similar  to 
tin1  former  case,  except  that  the  end  of  the  sand  bank  beyond  the  breakwater  was 
slightly  eroded,  whilst  deposit  took  place  between  the  extended  training  wall  and 
the  breakwater.  (Compare  Fig.  101  with  Fig.  100.) 


Fig.  102. — Scheme  C. 


(157)  Scheme  C.— The  third  arrangement  of  training  walls  experimented  upon  in 
the  model  was  chosen  from  a design  published  in  1885.*  It  consisted  of  an  en- 
largement of  the  original  trained  channel  below  Quillebeuf,  by  a modification  of 
the  southern  training  wall  from  Quillebeuf,  and  of  the  northern  training  wall  from 
Tanearville,  and  the  extension  of  the  northern  wall  to  Amfard  and  Havre,  and  the 
southern  training  wall  to  Ratier,  as  shown  on  Fig.  102.  The  trained  channel  was 
thus  given  a curved,  gradually  enlarging  form,  and  was  directed  into  the  central 
channel  of  the  model,  between  Ratier  and  Amfard,  the  Villerville  and  Havre  chan- 
nels being  practically  closed  near  low  water.  The  effects  of  working  the  model  for 
about  6.500  tides  with  this  arrangement  of  training  walls  are  indicated  on  the  chart 
(Fig.  102).  The  main  channel  kept  near  the  concave  southern  training  wall  for 
some  distance  below  Berville,  and  then  gradually  assumed  a more  central  course 
between  the  training  walls  towards  the  outlet,  passing  out  just  to  the  south  of  the 
Amfard  bank.  The  channel  thus  formed  had  a good,  tolerably  uniform  depth, 
together  with  a fair  width,  owing  apparently  to  the  flood  and  ebb  tides  produced 
in  the  model  following  an  unimpeded  and  fairly  similar  course.  Deposit  occurred 
behind  the  training  walls  on  each  side;  and  the  foreshore  advanced  in  front  of 
Trouville  in  the  model,  inconsequence  of  the  shutting  up  of  the  Villerville  Channel. 


* La  Seine  Maritime  et  son  Estuaire,  E.  Lavoinne,  Paris,  1885,  p.  140,  and  Instit. 
Civ.  Engin.  Proc.,  Vol.  84,  p.  248,  and  PI.  4,  Fig.  9. 


CIVIL  ENGINEERING,  ETC. 


663 


(158)  Scheme  D. — The  fourth  arrangement  of  training  walls  adopted  in  the  model 
was  selected  from  the  most  recent  design*  proposed  by  an  engineer  who  had  pre- 
viously submitted  schemes  in  1881f  and  18864  The  trained  channel  was  widened 
out  by  an  alteration  of  the  southern  wall  from  Quillebeuf,  and  the  northern  wall 
from  Tancarville,  more  than  trebling  the  width  between  the  training  walls  at  Ber- 
ville  in  the  model;  and  the  walls  were  extended  in  sinuous  lines  to  Havre  on  the 
northern  side,  and  Honfleur  on  the  southern  side,  as  shown  on  Fig.  103,  thus  form- 
ing a winding  trained  channel  rapidly  enlarging  near  its  outlet.  The  model,  with 


Fio.  103.— Scheme  D. 


these  lines  of  training  walls,  was  worked  for  about  5,000  tides,  with  the  results  indi- 
cated on  the  chart.  Deep  channels  were  scoured  out  close  along  the  inner  concave 
faces  of  the  training  walls  in  the  model;  but  shoals  appeared  over  a considerable 
area  of  the  newly  trained  channel;  a bar  stretched  across  the  deep  channel  where  it 
shifted  over  from  the  south  to  the  north  training  wall,  about  half  way  between 
Berville  and  Ilonfleur;  and  a large  sand  bank,  emerging  above  low  water,  occupied 
the  center  of  the  outlet  opposite  Honfleur.  Deposit  also  occurred  at  the  sides  of  the 
estuary  behind  training  walls. 

(159)  As  it  was  of  importance  to  ascertain  to  what  extent  accidental  modifications 
in  the  arrangement  of  the  sand  in  the  preparation  for  an  experiment  might  affect 


Fio.  1(M.— Scheme  D bis. 


the  result,  the  lines  of  training  walls  described  above  were  inserted  a second  time 
in  the  model,  after  the  subsequent  scheme  E had  been  experimented  upon,  render- 

* Deposition  de  M.  Vauthier  devant  la  Commission  des  Ports  et  Voies  Navigables 
de  la  Chambre  des  Deputes,  Paris,  1888,  p.  17,  and  PI.  4. 

t Rapport  sur  les  Ameliorations  dont  sont  encore  susceptibles  la  Seine  Maritime 
et  son  Estuaire,  L.  L.  Vauthier,  Rouen.  1881,  p.  16.  and  Annex  29. 

| Dire  a l'Enquete  ouverte  sur  l'Avant-projet  des  Travaux  d'Amelioration  de  la 
Basse-Seine,  1886,  L.  L.  Vauthier,  Paris,  PI.  1. 


664 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


ing  it  necessary  to  replace  afresh  both  training  walls,  and  to  remodel  the  sand  so  as 
to  represent  approximately  the  present  condition  of  the  estuary.  The  model  was 
prepared  for  this  second  experiment  in  the  usual  way,  without  any  special  endeavor 
to  secure  coincidence  with  the  first  experiment  in  the  initial  arrangement  of  sand 
banks  and  channels.  The  condition  of  the  low-water  channels  in  the  model,  after 
working  the  model  with  this  arrangement  of  training  walls  for  the  second  time  for 
about  5,400  tides,  is  shown  on  Fig.  104.  The  main  features  of  the  trained  channel 
in  the  charts  of  the  two  experiments  exhibit  a very  fair  resemblance,  considering 
the  modifications  which  any  alterations  in  the  initial  condition  might  produce,  and 
the  naturally  variable  state  of  the  channels  in  a wide  outlet.  The  deep  channels 
reappear  in  the  second  chart  at  the  inner  concave  faces  of  the  training  walls,  with 
intervening  shoals;  a large  sand  bank  is  again  visible  at  low  water  along  the  north 
training  wall  opposite  La  Roque  and  Berville  in  the  model;  anil  the  sand  bank  in 
the  center  of  the  outlet  of  the  trained  channel  opposite  Honfleur  emerges  again, 
though  smaller  in  extent  owing  to  alterations  in  the  channel;  and  the  deep  place  at 
the  end  of  the  southern  training  wall  close  to  Honfleur  is  the  same  in  both  charts. 

(160)  Scheme  E. — The  fifth  arrangement  of  training  walls  introduced  into  the 
model  was  taken  from  a design*  published  in  1888,  which  is  a modification  of  a 


Fig.  105. — Scheme  E. 


scheme,  presented  in  1886,  by  a committee  of  experts  appointed  by  the  French  Gov- 
ernment to  consider  the  question. f In  the  scheme  as  laid  down  in  the  model  the 
trained  channel  in  the  bend  between  Quillebeuf  and  Tancarville,  where  the  depth 
was  greatest,  was  enlarged  in  width  by  setting  back  the  southern  training  wall;  the 
original  width  of  the  channel  was  retained  at  the  point  of  inflection  opposite  Tancar- 
ville, and  the  channel  was  widened  out  below  La  Roque  by  a modification  of  the 
lines  of  both  training  walls  down  to  Berville.  The  training  walls  were  also  extended 
beyond  Berville  in  sinuous  lines,  as  shown  on  Fig.  105,  the  southern  wall  being  car- 
ried down  to  Honfleur,  and  the  northern  Wall  not  quite  so  far.  The  portion  form- 
ing the  last  bend  of  the  northern  training  wall  was  kept  low,  whilst  the  others 
were  made  high,  according  to  the  design.  Both  in  this  and  the  preceding  arrange- 
ment of  training  walls  experimented  on  the  expanding  trained  channel  was  some- 
what restricted  in  width  along  the  portions  near  the  changes  of  curvature,  to  make 
it  conform  to  the  principles  which  experience  has  laid  down  for  training  winding 
rivers  in  their  nontidd  course,  as  previously  mentioned.  The  results  obtained, 


*De  l’Amelioration  du  Port  dil  Havre  et  des  Passes  de  la  Basse-Seine.  Baron 
Quinette  de  Rochemont,  Paris,  1888,  excerpt  Memoires  de  la  Societe  des  Ingenieurs 
Civils,  1888,  p.  334,  PI.  162,  Fig.  1. 

f Commission  d’Etude  des  Ameliorations  a apporter  an  Port  du  Havre  et  aux 
Passes  de  la  Basse-Seine — Raport  de  la  Commission,  Paris,  1886,  p.  61,  and  chart. 


CIVIL  ENGINEERING,  ETC. 


(i<>5 

after  working  the  model  for  about  3.700  tides,  are  represented  on  the  chart  (Fig. 
10.r>).  The  channel  between  the  training  walls  was  somewhat  shallow  in  places, 
and  though  a deep  channel  was  formed  along  the  inner  concave  face  of  the  south- 
ern wall  between  La  Roque  and  Berv  lie,  a shoal  emerging  above  low  water  appeared 
along  the  concave  face  of  the  last  bend  of  the  northern  training  wall.  This  bank 
appeared  to  be  due  to  the  protection  the  extremity  of  the  bend  afforded  from  the 
action  of  the  flood  tide  in  the  model,  whilst  the  ebb  followed  the  central  Hood-tide 
channel,  instead  of  passing  over  to  the  concave  bank,  as  would  have  occurred  with 
the  current  of  a nontidal  river.  The  main  channel  beyond  the  training  walls, 
which,  though  of  fair  depth,  was  somewhat  narrow  and  winding,  was  also  unsta- 
ble, for  in  the  early  part  of  the  experiment  its  outlet  was  in  the  central  channel 
between  Ratier  and  Amfard  in  the  model,  whilst  at  the  close  of  the  experiment  it 
had  shifted,  as  shown,  to  the  Havre  Channel.  Accretion  occurred  behind  tin-  train- 
ing walls  in  the  model,  and  some  silting  up  took  place  in  the  Villerville  Channel 
and  along  the  foreshore  in  front  of  Trouville,  owing  apparently  to  the  preference  of 
the  main  channel  for  the  other  outlets,  and  the  diminished  capacity  of  the  estuary 
resulting  from  accretion. 

(101)  This  arrangement  of  training  walls  was  further  investigated  by  workingthe 
model  for  about  0,300  tides  more,  with  the  results  shown  on  Fig.  106.  The  chief  fea- 
tures of  the  estuary  in  the  model  showed  only  slight  changes  from  the  state  previ- 


Fio.  106. — Scheme  K bis. 


ously  recorded  (Fig.  105),  with  the  exception  of  the  main  channel,  which  had  shifted 
again  to  the  central  outlet,  whilst  the  northern  foreshore  above  low  water  extended 
over  part  of  the  former  site  of  the  channel.  The  two  conditions  of  the  estuary, 
represented  by  Figs.  105  and  106,  have  therefore  the  interest  of  exhibiting  in  the 
model  a shifting  channel  such  as  actually  exists  at  the  present  time  in  the  Seine 
estuary  below  Berville. 

(162)  Scheme  F. — The  last  experiment  was  made  on  an  arrangement  of  training 
walls  inserted  in  the  model,  making  the  trained  channel  expand  as  gently  as  practi- 
cable between  Aizier  and  the  sea,  whilst  retaining  the  natural  width  at  the  outlet 
(Fig.  107).  This  is  the  form  of  channel  which  theory  indicates  as  the  most  suitable.* 
for  whilst  it  facilitates  the  influx  of  the  Hood  tide,  it  prevents,  as  far  as  possible,  the 
abrupt  changes  in  the  velocity  of  a river  in  passing  from  its  estuary  to  the  sea.  which 
are  so  prejudicial  to  uniformity  of  depth  in  a channel.  It  was  therefore  of  interest 
to  ascertain  what  results  would  be  produced  by  this  theoretical  arrangement  of 
training  walls  in  the  model,  which,  in  order  to  leave  the  outlet  free,  and  thus  avoid 
favoring  a progression  of  the  foreshore  outside,  had  to  provide  a wide  channel 
near  Honfleur  compared  with  the  restricted  width  available  at  Quillebeuf.  The  di- 
rection of  the  channel  between  Aizier  and  Quillebeuf,  together  with  the  cliffs  bor- 
dering the  river  at  Quillebeuf  and  Tancarville  Points,  determined  the  maximum 
width  obtainable  at  Quillebeuf  and  the  direction  of  the  channel  from  Aizier  to  Tan- 


Rivers  and  Canals,  L.  F.  Vernon-Harcourt,  p.  236. 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


666 

carville;  and  the  extension  of  the  training  walls  in  the  model  from  this  point  was 
regulated  by  the  necessity  of  passing  close  to  Honfleur  at  the  south,  and  not  im- 
peding the  approach  to  Havre  on  the  north.  The  effects  produced  in  the  model  by 
working  with  this  arrangement  of  training  walls  for  al>out  7,300  tides  are  indicated 
on  the  chart  ( Fig.  107).  The  southern  training  wall  was  kept  above  high-water  level 
all  the  way  to  its  termination  at  Honfleur  in  the  model,  hut  the  northern  training 
wall  was  gradually  reduced  in  height  from  nearly  opposite  Honfleur  towards  Havre. 
The  trained  channel  had  a good  width  at  low  water  throughout,  in  spite  of  the  dis- 
tance apart  of  the  training  walls  in  the  model,  the  whole  channel  being  below 
low-water  level,  except  near  the  southern  wall  between  Berville  and  Havre,  and 
against  the  northern  wall  nearly  opposite  Hoc  Point,  where  banks  emerged  slightly 
above  low  water.  The  channel,  moreover,  was  distinctly,  though  slowly,  improv- 
ing with  the  continuance  of  the  working,  and  the  banks  diminishing.  There  was 
also  a fair  depth  in  the  channel,  the  shallowest  place  being  opposite  Berville,  whilst 
a deep  place  was  formed  just  above,  near  the  southern  wall  between  La  Roque  and 
Berville.  The  depth  in  all  the  outlet  channels  was  well  maintained;  and  though 
deposit  naturally  took  place  behind  the  northern  training  wall,  no  accretion  was 
visible  along  the  foreshores  outside. 


Fig.  107.— Scheme  F. 


CONSIDERATIONS  AFFECTING  EXPERIMENTAL  TRAINING  WORKS. 

(163)  The  value  of  experiments  resembling  those  just  described  depends  entirely 
upon  the  extent  to  which  they  maybe  regarded  as  producing  effects  approximately 
corresponding,  on  a small  scale,  to  those  which  training  works  on  similar  lines,  if 
carried  out  in  an  estuary,  would  actually  produce.  If  the  effects  of  any  training 
works  could  be  foreshadowed  by  experiments  in  a model,  the  value  of  such  experi- 
ments, in  guiding  engineers  towards  the  selection  of  the  most  suitable  design,  could 
not  be  overestimated. 

Some  of  the  influences  at  work  in  an  estuary  can  not  possibly  be  reproduced  in  a 
model — such  as  winds  and  waves.  Winds  coming  from  different  quarters  are  va- 
riable in  their  effects;  but  the  direction  of  the  prevailing  wind  indicates  the  line  in 
which  the  action  of  the  wind  has  most  influence,  which  may  be  exerted  in  reenforc- 
ing the  flood  or  ebb  currents,  and  may  aid  or  retard  accretion  bv  blowing  the  silt- 
bearing stream  more  into  or  out  of  the  estuary.  Waves  are  the  main  agents  in  the 
erosion  of  cliffs  along  open  seacoasts,  and  in  stirring  up  sand  in  shallow  places; 
and  the  material  thus  put  in  suspension  may  be  transported  by  tidal  currents,  aided 
by  wind,  into  an  estuary,  and  be  deposited  under  favorable  conditions.  These  cir- 
cumstances affect  the  rate  of  accretion,  which  can  not  be  investigated  experiment- 
ally, as  it  is  impossible  to  reproduce  in  a model  the  proportion  of  silt  in  suspension, 
which,  moreover,  varies  in  any  estuary  with  the  state  of  the  weather  and  tide,  and 
the  volume  of  fresh  water  discharged.  Inside  an  estuary,  also,  waves  in  storms 
may  erode  the  shores  at  high  tide,  and  modify  the  low-water  channels;  but  the  first 


CIVIL  ENGINEERING,  ETC. 


667 


effect  is  very  gradual,  and  the  second  is  intermittent,  only  occasionally  occurring. 

The  main  forces  acting  in  any  tidal  estuary  are  the  tidal  ebb  and  flow  and  the 
fresh-water  discharge,  which  are  constantly  at  work;  and  they  regulate  the  size  of 
the  channels  in  an  estuary,  and  for  the  most  part  their  direction,  as  well  as  the 
limits  of  accretion.  These  are  the  forces  which  can  be  reproduced  in  miniature  in 
a model,  as  proved  by  the  close  concordance  in  the  channels  obtained  by  experiment 
with  the  actual  conditions  of  the  Mersey,  and  with  a previous  state  of  the  Seine 
estuary;  and  this  similarity  of  results  would  not  have  occurred  if  the  other  influ- 
ences noticed  above  were  at  all  equally  potent. 

Training  walls  mainly  modify  the  direction  and  action  of  the  tidal  ebb  and  flow 
and  fresh-water  discharge;  and  therefore  it  is  reasonable  to  suppose  that  the  re- 
sults in  a model,  due  to  these  alterations,  would  correspond  to  their  actual  effects 
in  an  estuary,  provided  the  important  element  of  accretion  could  be  also  reproduced. 
This  was  satisfactorily  accomplished  in  the  second  stage  of  the  investigation,  prov- 
ing that  the  miniature  influences  produced  in  the  model  corresponded,  in  this  case 
also,  with  the  forces  acting  in  the  estuary.  Accretion  is  promoted  by  training  walls 
in  an  estuary  where  matter  is  carried  in  suspension;  but  the  action  of  waves  in 
modifying  the  channels  is  stopped  by  the  intervention  of  training  walls.  Accord- 
ingly, the  further  the  training  walls  are  extended,  and  the  more  an  estuary  is  pro- 
tected by  works  such  as  those  indicated  in  Figs.  99-101,  the  more  is  the  modifying 
influence  of  waves  eliminated,  and  therefore  the  more  are  experiments  in  a model 
likely  to  correspond  with  the  conditions  of  estuaries  under  similar  conditions. 

(104)  Other  considerations  also  afford  grounds  for  supposing  that  the  effects  ob- 
served with  training  walls  in  a model  fairly  correspond  with  the  results  which  such 
works  would  produce  in  an  estuary.  The  chartsof  the  experiments  show  that  defi- 
nite results  followed  from  certain  lines  inserted  in  the  model,  and  that  modifications 
in  these  lines  were  followed  by  modifications  in  results.  (Compare  Figs.  99-101  and 
Fig.  103  with  Fig.  105.)  Moreover,  the  results  produced  with  the  model  agree  very 
closely  with  the  results  which,  in  the  two  earliest  schemes  experimented  upon,  it 
was  stated,  before  the  experiments  were  begun,  would  follow,  if  the  works  indi- 
cated by  lines  in  the  charts  were  actually  carried  out  in  the  Seine  estuary.* 

* Compare  the  observations  relating  to  Scheme  A and  Fig.  99,  with  the  follow- 
ing extract  from  Instit.  Civ.  Engin.  Proc.,  vol.  84,  p.356:  “Thenarrowing  of  the 
mouth  of  the  estuary  of  the  Seine  would  at  first  promote  scour,  and  increase 
the  depth  in  that  part  of  the. channel,  and  for  a little  distance  above  and  below. 
This  contraction,  however,  would  impede  the  influx  of  the  flood  tide,  and  cause 
changes  in  the  velocity  of  the  current  through  the  narrow  neck,  and  in  the  wide 
estuary  above,  promoting  the  deposit  of  silt  brought  in  by  the  tide.  This  accretion 
would  be  greatly  aided  by  the  prolongation  of  the  training  walls  to  Ilonfleur,  so 
that  eventually  the  greater  portion  of  the  estuary  comprised  between  Tancarville, 
Hoc  Point,  and  Honfleur  would  be  raised  to  high-water  level.  This  large  reduction 
in  tidal  capacity  would  reduce  the  tidal  current  through  the  narrowed  entrance,  and 
consequently  diminish  again  the  depth  in  the  channel.  Moreover,  this  reduction  of 
tidal  flow  in  and  out  of  the  lower  estuary  would  favor  the  natural  heaping-up  action 
of  the  sea  on  the  sands  outside:  so  that  eventually,  not  only  would  the  initial  deep- 
ening of  the  narrowed  outlet  be  lost,  but  the  good  depths  in  the  bay  outside  the 
estuary  would  be  imperiled.” 

Compare  also  Fig.  102,  with  the  following  extract  from  Instit. Civ.  Engin.  Proc., 
vol.  84,  p.  250:  “The  continuously  concave  southern  training  wall,  whilst  very 
favorable  to  Honfleur.  will  unduly  keep  the  ebb  current  to  that  side,  and  there- 
fore away  from  Havre.  Also,  the  extension  of  the  wall  along  the  Ratier  Bank 
will  act  like  a groyne,  and,  arresting  the  silt-bearing  southern  current,  will  connect 
Trouvilie  Bank  with  the  shore,  and  lead  to  a large  accumulation  of  deposit  in  front 
of  Trouville.  * * * and  also  the  low  walls  proposed  will  not  prevent  accretion.” 


608 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


It  would  be  impossible  to  determine  by  experiment  the  time  any  changes  in  an 
estuary  would  occupy.  The  figures,  in  fact,  giving  the  number  of  tides  during  which 
each  experiment  was  worked,  are  not  even  intended  as  an  indication  of  the  rate  of 
change  in  the  model,  and  much  less  as  any  measure  of  the  period  required  for  such 
changes  in  an  estuary,  but  merely  as  a record  of  the  comparative  duration  of  each 
experiment.  It  was  observed,  however,  that  the  changes  were  most  rapid  where 
the  modifications  effected  by  the  lines  of  walls  inserted  in  the  model  were  greatest 
(Figs.  99-101),  and  slowest  where  the  lines  in  the  model  produced  the  least  altera- 
tions. (Figs.  102  and  107.) 

PRINCIPLES  FOR  TRAINING  TIDAL  RIVERS  DEDUCED  FROM  EXPERIMENTS. 

(165)  The  foregoing  investigations,  viewed  merely  as  experiments,  without  any 
reference  to  their  hearing  ou  the  Seine,  may  serve  for  indicating  some  general  prin- 
ciples applicable  in  training  tidal  rivers  through  wide  estuaries.  Direct  experiment 
for  each  estuary  is  undoubtedly  preferable  to  abstract  reasoning,  where  such  experi- 
ment is  possible,  as  it  reproduces  the  special  conditions  of  the  estuary  to  lie  in- 
vestigated. Nevertheless  general  principles  may  be  of  value  in  guiding  the  choice 
of  designs  to  be  investigated,  so  as  to  avoid  waste  of  time  in  testing  unfavorable 
schemes,  and  also  in  cases  where  the  conditions  of  an  estuary  are  not  sufficiently 
known  to  afford  a correct  basis  for  experiment. 

The  experiments  may  be  divided  into  three  classes,  namely: 

(1)  Outlet  of  estuary  considerably  restricted,  and  channel  trained  inside  toward 
outlet.  (Figs.  99-101.) 

(2)  Channel  trained  in  sinuous  line,  expanding  towards  outlet,  but  kept  somewhat 
narrow  at  changes  of  curvature.  (Figs.  103-106.) 

(3)  Channel  trained  in  as  direct  a course  as  practicable,  and  expanding  regularly 
to  outlet.  (Figs.  102  and  101.) 

The  experiments  of  the  first  class  exhibited  a deep  outlet,  and  a fairly  continuous 
channel  inside,  where  the  training  works  were  prolonged  to  the  outlet.  The  chan- 
nel, however,  was  irregular  in  depth  near  the  outlet;  and  a bar  appeared  in  front 
of  the  outlet  outside.  The  breakwater  also,  extending  across  part  of  the  outlet,  fa- 
vored deposits  both  inside  and  outside  the  estuary,  by  producing  slack  water  in  the 
sheltered  recesses. 

The  second  class  of  trained  channel  was  designed  to  profit  by  the  scour  at  the 
concave  face  of  bends,  so  clearly  exhibited  at  the  first  bend  of  all  the  charts,  and 
to  continue  the  depth  thus  obtained  by  restricting  the  width  between  the  bends,  on 
the  principle  adopted  for  winding  nontidal  rivers.  Experiment,  however,  did  not 
bear  out  the  advantages  anticipated  from  this  system,  probably  owing  to  the  varia- 
ble direction  of  the  flood  tide  at  different  heights  of  tide,  its  being  checked  in  its 
progress  by  the  winding  course,  and  not  acting  in  unison  with  the  ebb  from  the  dif- 
ference in  its  direction  and  the  width  of  the  trained  channel  near  the  outlet.  The 
main  stream  in  a nontidal  winding  river  always  follows  a tolerably  definite  course; 
whereas  the  flood  tide  tends  gradually,  as  it  rises,  to  assume  as  direct  a course  as 
possible.  The  difference,  therefore,  in  the  conditions  of  a nontidal  and  tidal  river, 
in  this  respect,  is  considerable. 

(166)  The  third  class  of  trained  channel  afforded  a wide,  tolerably  uniform  chan- 
nel in  the  experiments;  the  flood  tide  was  less  impeded  in  its  progress  than  with 
the  other  forms  of  training  walls,  and  appeared  to  act  more  in  concert  with  the  ebb. 

Tie  experiments,  accordingly,  indicate  that  the  only  satisfactory  principle  for 
training  rivers,  through  wide  estuaries  with  silt-bearing  currents,  is  to  give  the 
trained  channel  a gradually  expanding  form,  with  as  direct  a course  as  possible  to 
the  outlet.  The  rate  of  increase  of  width  between  the  training  walls  must  la*  de- 
termined by  the  special  conditions  of  the  estuary.  If  the  outlet  is  very  wide  and 
the  gradual  expansion  in  width  can  not  be  commenced  a considerable  distance 


CIVIL  ENGINEERING,  ETC. 


669 


up  an  estuary,  some  restriction  in  width  at  the  outlet  may  be  expedient  to  avoid  a 
too-rapid  expansion.  It  is  evident  that  the  widening  out  adopted  in  the  last  experi- 
ment (Fig.  107)  was  carried  to  its  utmost  limits,  from  the  continuance  of  sand  hanks 
inside  the  trained  channel,  and  that,  regarding  merely  the  improvement  of  the 
channel,  it  might  have  been  preferable  to  restrict  its  width  at  the  outlet  as  effected 
in  Scheme  C (Fig.  102).  At  the  same  time  it  must  not  be  inferred  from  the  ex- 
istence of  these  sandbanks  that  the  distance  apart  of  the  training  walls  was  much 
too  great  in  the  last  experiment;  for  the  width  apart  of  the  training  walls  necessi- 
tated the  inclusion  of  a greater  extent  of  sand  banks  within  the  trained  channel  at 
the  outset,  and  also  rendered  the  rate  of  improvement  in  the  channel  more  gradual, 
so  that  the  improvement  in  the  channel  both  in  direction  and  depth  was  still  pro- 
gressing at  the  close  of  the  experiment,  and  the  sand  banks  in  the  channel  were  in 
process  of  removal  and  not  being  formed.  The  choice  in  such  cases,  where  the 
widening. out  can  not  be  commenced  far  up,  appears  to  lit*  between  the  utmost  im- 
provement of  the  channel  at  the  expense  of  accretion  on  the  foreshores  outside  and 
the  maintenance  of  the  depths  over  the  foreshores  beyond  the  outlet,  accompanied 
with  a somewhat  less  good  channel  in  the  estuary.  In  some  cases,  deposit  on  the 
foreshores  at  the  side  beyond  the  outlet  might  be  of  no  importance,  and  then  the 
river  channel  should  be  primarily  considered;  but  if,  on  the  contrary,  accretion  on 
the  foreshores  outside  is  undesirable,  the  outlet  must  be  maintained  by  a greater 
widening  out  of  the  training  walls.  The  actual  direction  of  the  training  walls  must 
be  determined,  in  each  case,  by  the  general  direction  of  the  channel  above,  the  situ- 
ation of  ports  on  the  estuary,  the  position  of  the  outlet,  and  the  set  of  the  flood  tide 
at  the  entrance. 

(107)  Concliuiing  remarks. — In  terminating  this  record  of  my  investigations  and 
the  general  principles  for  training  works  which  they  seem  to  indicate,  I desire  to 
acknowledge  the  care  with  which  my  assistant,  Mr.  E.  Blundell,  lias  carried  out  the 
tedious  task  of  working  the  tides  in  the  model,  and  prepared  the  charts  of  the  ex- 
perimental results  from  which  the  illustrations  accompanying  this  paper  have  been 
drawn  out.  Eddies  at  sharp  edges,  due  to  distortion  of  scale,  appear  to  have  exces- 
sive scouring  effect  in  a model;  whilst  the  action  of  the  more  regular  currents  ex- 
hibits a deficiency  in  scouring  power,  as  previously  noted.  Though  the  actual 
depths  of  the  channels,  however,  are  too  small  for  the  distorted  vertical  scale,  re- 
liance, I think,  maybe  placed  on  the  general  forms  and  relative  depths  of  the  chan- 
nels obtained  in  a model.  It  is  possible  that  the  inadequate  depth  might  he  reme- 
died by  the  employment  of  a finer  or  lighter  material  for  forming  the  l>ed  of  the 
model,  or  by  using  a liquid  of  greater  density  than  water;  but  sand  and  water  have 
the  unquestionable  advantage  of  being  the  substances  which  actually  effect  the 
changes  in  estuaries. 


PART  II— TIDAL,  COAST,  AND  HARBOR  WORKS. 


Chapter  XVIII. — Calais  Harbor  Works. 

(108)  In  1875,  before  the  beginning  of  the  improvements  just  fin- 
ished, the  condition  of  the  port  was  as  follows:  The  depth  in  the  outer 
channel  on  the  bar,  maintained  by  the  action  of  the  littoral  currents 
and  that  of  the  sluicing  basin,  varied  from  zero  to  0.75  meter  below 
the  zero  of  the  charts  (this  zero  being  the  mean  level  of  the  Medi- 
terranean at  Marseilles).  The  other  depths  below  this  datum  were 
as  follows: 

Channel  between  the  jetties.  1.50  to  2.50  meters  below  zero. 

At  the  foot  of  the  wharf  built  against  the  western  jetty  for  the  channel  mail 
steamers,  3 meters  below  zero. 

In  the  outer  harbor,  0.72  meter  above  zero. 

In  the  dock,  0.72  meter  above  zero. 

Total  length  of  the  quays,  2,330  meters. 

Area  of  the  western  dock,  2 hectares. 

The  entrance  lock  to  this  dock,  17  meters  wide,  had  a single  pair 
of  gates,  and  could  only  be  used  by  vessels  during  one  or  two  hours 
of  high  tide.  The  rise  of  the  tide  is  about  7 meters.  The  width  of 
the  quays  did  not  anywhere  exceed  30  meters,  which  was  entirely  too 
narrow  for  the  traffic  along  the  Calais-Dover  route,  requiring,  as  it 
did,  branch  lines,  sidings,  and  facilities  for  transporting  the  freight 
between  the  ships  unloading  and  the  Calais  station. 

Also,  there  were  no  adequate  means  of  communication  between 
the  port  and  the  network  of  water  ways  connected  with  it,  so  that  in 
181 5 the  total  tonnage  entering  and  leaving  the  port  was  840,000  tons, 
but  the  weight  of  merchandise  imported  and  exported  did  not  ex- 
ceed 215,000  tons. 

For  want  of  sufficient  depth  on  the  bar  the  mail  service  between 
Dover  and  Calais  was  the  only  one  which  could  be  run  at  fixed  hours 
day  and  night,  and  even  this  was  more  or  less  irregular. 

The  new  works,  created  in  virtue  of  the  laws  of  December  14,  1875, 
and  August  3,  1881,  which  are  now  completed,  have  wholly  changed 
670 


CIVIL  ENGINEERING,  ETC.  671 

the  condition  of  the  port  from  what  it  was  14  years  ago.  These 
new  works  (see  Fig.  103)  may  be  described  as  follows  : 

(169)  Exterior  and  interior  channel. — By  dredging,  and  bv  the 
combined  action  of  the  two  sluicing  basins,  a minimum  depth  of  4 


672 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


(170)  Scouring  or  sluicing  basin. — The  sluicing  basin  lias  an  area 
of  90  hectares  ; it  has  been  excavated  to  a depth  of  5 meters  above  the 
zero  of  the  charts,  except  in  the  center  where  a deeper  channel  has 
been  made  to  the  opening  of  the  sluicing  lock. 

The  volume  of  available  water  stored  at  high  tide  above  the  ref- 
erence + 5 is  1,000,000  cubic  meters.  This  volume  can  be  dis- 
charged, with  a fall  of  from  4.25  to  G meters,  in  from  45  to  00  min- 
utes. 

(171)  The  sluicing  lock  is  made  with  five  openings,  each  0 meters 
wide,  closed  by  balance  gates  turning  around  a central  axle  The 
sill  of  these  openings  is  placed  at  low-water  level,— 0.72  meter.  The 
sluicing  water  is  so  directed  as  to  strike  upon  the  inner  channel,  250 
meters  from  the  extremities  of  the  jetties,  where  a great  deal  of  sand 
is  deposited,  and  where  the  dredging  is  difficult.  The  sand  is  cur- 
ried to  the  bar,  whence  it  is  easily  removed  by  dredges. 

(172)  Outer  harbor. — The  new  outer  harbor  has  an  area  of  0 hec- 
tares; it  is  bordered  on  the  northeast  and  southwest  by  quays  which 
are  connected  by  return  walls  to  the  entrance  lock  of  the  eastern 
dock.  The  mean  width  is  100  meters,  and  the  depth  4 meters  below 
zero,  except  at  the  foot  of  the  southwestern  quay,  where  the  channel 
is  cut  7 meters  deep  to  allow  large  ships  to  remain  afloat. 

This  quay  is  240  meters  long,  and  its  foundations  are  sunk  10 
meters  below  zero.  Here  sheds  are  built  and  rails  laid  for  the  use 
of  ocean  steamships,  so  that  they  can  call  at  Calais,  and  can  load 
and  unload  without  entering  the  dock.  The  northeast  quay  is  for 
the  steamboat  service  between  Calais  and  Dover,  and  contains  the 
railroad  station,  and  berths  for  four  steame-rs  from  100  to  120  meters 
long,  drawing  3.50  meters.  The  quay  itself  is  370  meters  long  and 
has  a depth  of  3.5  meters  at  its  foot. 

(173)  Eastern  dock. — Entrance  to  the  eastern  dock  is  obtained  by 
means  of  two  parallel  locks  whose  sills  are  placed  1.75  meters  below 
zero ; their  depth  is  5. 70  meters  below  the  mean  sea  level  (3. 92  meters) 
and  their  widths  are  21  and  14  meters,  respectively;  they  will  lock 
ships  135  meters  long,  and  are  each  divided  by  a pair  of  intermediate 
gates,  so  as  to  economize  the  water  when  locking  small  vessels.  At 
high  tide  vessels  can  go  through  the  locks.  The  gates,  capstans, 
drawbridges,  etc.,  are  worked  by  hydraulic  machinery. 

The  area  of  this  dock  is  12  hectares,  including  the  inner  basin,  with 
which  it  communicates.  Its  width  is  170  meters  at  the  entrance,  120 
at  its  southern  extremity,  and  70  in  the  inner  basin  ; close  to  the  locks 
the  width  is  increased  so  as  to  give  more  room  to  vessels  entering  or 
leaving. 

The  depth  is  0.50  meter  below  the  sills.  The  total  length  of  the 
quays  around  this  dock  is  1,500  meters. 

The  inner  basin  is  excavated  to  low-water  level,  and  the  effective 
length  of  the  surrounding  quays  is  350  meters.  The  width  of  the 
western  quay  is  100  meters  and  that  of  the  eastern  140. 


CIVIL  ENGINEERING,  ETC. 


073 

(174)  Sheds  are  constructed  on  the  west  side  by  the  chamber  of 
commerce,  and  all  quays  are  provided  with  railroad  tracks  by  the 
Northern  Railroad  Company. 

(175)  Graving  dock. — A dry  dock  155  meters  long,  entered  through 
a lock,  can  accommodate  vessels  150  meters  long.  It  is  provided 
with  pumping  machinery  arranged  so  as  to  empty  the  dock  in  3 
hours. 

(17G)  Canal  dock. — Between  the  east  and  west  docks  is  a canal 
dock,  covering  4 hectares,  for  the  use  of  barges;  it  is  surrounded  by  a 
quay  1,000  meters  long,  and  extends  from  the  new  eastern  dock, 
with  which  it  is  connected  by  two  locks,  to  the  citadel  canal,  by 
which  it  communicates  with  the  citadel  lock  and  the  old  port. 

Communication  between  this  dock  and  the  citadel  lock  can  be  cut. 
off  by  means  of  a guard  lock,  the  gates  of  which  may  be  moved 
whatever  may  be  the  force  of  the  current,  thus  forming  a dam  in 
case  of  accident  to  the  citadel  lock,  either  against  the  sea  or  against 
the  water  in  the  dock. 

(177)  The  Pierrettes  canal  runs  into  the  citadel  lock  below  the 
guard  lock.  It  may  be  used  to  separate  the  old  sluicing  basin  from 
the  drainage  canal.  The  gates  of  the  guard  lock  are  closed  against 
the  water  in  the  basin,  when  the  Pierrettes  canal  is  used  to  discharge 
its  flood  waters  into  the  sea  through  the  citadel  lock,  the  level  of 
this  canal  being  1 meter  below  the  Calais  canal.  The  Pierrettes 
canal  is  usually  kept  closed  by  a movable  dam. 

Five  bridges,  two  of  which  cross  the  locks,  provide  for  the  traffic 
between  the  two  sides  of  the  canal. 

(178)  The  Marck  canal,  which  receives  nearly  all  the  surface  water 
from  the  lowlands  on  the  right^of  the  Calais  canal,  formerly  dis- 
charged through  a bridge  dam  into  the  Calais  canal,  in  the  center 
of  the  town  of  St.  Pierre.  The  water  could  run  into  the  sea  through 
the  citadel  lock  only  when  the  latter  was  being  emptied.  These 
waters  wrere  so  abundant  as  to  require  the  level  in  the  Calais  canal 
to  be  frequently  and  excessively  lowered.  To  avoid  this  and  pre- 
serve a constant  level  in  the  Calais  canal  in  times  of  freshet,  the 
Marck  canal  has  been  diverted  so  as  to  discharge  directly  into  the 
outer  harbor.  The  Calais  canal  has  also  been  straightened,  enlarged, 
and  deepened  so  as  to  allow  the  passage  of  vessels  of  300  tons  burden, 
the  largest  that  can  be  accommodated  on  the  northern  water  ways 
between  Belgium  and  France. 

(179)  The  Calais  improvement  works  began  in  1870.  The  sluicing 
basin  and  its  lock,  the  outer  port,  the  lock  of  the  eastern  dock,  and 
the  northern  part  of  the  basin  itself,  had  to  be  constructed  on  the 
beach.  The  southern  portion  of  the  same  dock  had  to  be  excavated 
across  the  line  of  downs  and  the  works  which  protected  the  town  of 
St.  Pierre  from  the  sea  situated  about  2 meters  above  the  highest 
tide.  All  the  excavations  had  to  be  made  in  the  tine  beach  sand 

H.  Ex.  410— vol  in 


43 


<674 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


and  downs,  and  upon  it  the  harbor  works  had  to  rest.  Again  the 
foundations  could  not  be  made  without  protection  against  the  sea. 

Fortunately  the  contour  of  the  port  and  the  general  arrangement 
of  the  works  permitted  the  formation  of  a series  of  coffer  dams,  cor- 
responding to  several  groups  of  projected  improvements,  which 
•could  be  undertaken  separately.  The  utilization  of  the  first  fillings 
for  the  quays  and  permanent  dikes  as  coffer  dams,  greatly  reduced 
the  amount  of  temporary  earthwork.  The  slopes,  slightly  exposed 
to  the  sea,  were  covered  with  rocks  from  the  chalk  formation  and 
held  by  wattling.  When  more  exposed,  they  were  covered  with  sand 
resting  on  straw  so  placed  that  the  stalks  lay  in  the  direction  of  the 
greatest  slope,  and  were  held  by  horizontal  lines  of  wattling;  between 
these  lines  the  straw  was  loaded  with  hard  limestone,  pointed  and 
laid  in  courses  with  their  tails  downward,  and  strongly  rammed  to- 
gether. In  the  most  exposed  portion  the  revetment  of  the  slope  was 
formed  by  stone  pitching.  The  foot  of  the  slope  rested  against  a line 
of  sheet  piling  which  was  reinforced  by  a mass  of  beton  sunk  1.50 
meters  in  the  sand.  The  stone  pitching  was  laid  upon  a bed  of  well 
rammed  clay  0.30  meter  thick,  spread  upon  the  slope  to  prevent  the 
sand  from  being  washed  away.  This  pitching  was  0.50  meter  thick 
and  set  in  Portland  cement.  A curved  form  decreasing  in  declivity 
was  given  to  the  new  sea  front  of  the  dike  to  better  protect  it  against 
the  action  of  the  waves. 

The  engineers,  seeing  the  great  difficulty  of  driving  piles  through 
the  sand,  had  recourse  to  the  method  of  sinking  them  by  means  of 
water  jets. 

Before  using  the  water  jets,  to  drive  a panel  of  sheet  piling  2.50 
meters  high  and  180  long  required  900  blows  from  a ram  weigh- 
ing 600  kilograms,  and  occupied  from  3|  to  144  hours,  or  an  average 
of  84  hours.  The  resistance  of  the  sand  was  such  that  the  thickness 
of  the  piling  had  to  be  increased  from  0.08  to  0.12  meter,  and  even 
then  the  wood  was  frequently  broken. 

The  first  trials  of  the  jets  gave  such  remarkable  results  that  the 
method  was  subsequently  employed  to  sink  most  of  the  foundation 
walls  of  the  quays. 

The  water  jet  was  forced  into  the  sand  by  means  of  a hand  pump 
through  an  iron  nozzle  0.027  meter  in  diameter,  connected  to  an 
India-rubber  hose  (see  Plate  V).  This  so  facilitated  the  work  that 
a panel  of  seven  or  eight  planks  was  sunk  in  one  hour  and  nine  min- 
utes, and  in  many  cases  the  time  was  reduced  to  fifteen  minutes. 
The  number  of  blows  did  not  exceed  fifty,  and  were  only  necessary  to 
overcome  the  friction  between  adjacent  panels,  which  were  tongued 
and  grooved  to  make  a tight  joint.  The  weight  of  the  ram  on  a 
single  pile  3 meters  long  was  sufficient  to  sink  it  immediately,  and 
the  former  thickness  of  0.08  meter  for  the  panels  was  restored. 

This  dike  was  finished  without  accident,  but,  several  years  later. 


CIVIL  ENGINEERING,  ETC. 


675 


during  the  high  tide  of  an  equinoctial  storm  a great  breach  was 
made  in  it;  this  was  closed  and  the  profile  of  the  dike  modified  as 
shown  in  Fig.  109.  The  height  and  thickness  are  the  same  as  before, 


but  the  top  had  a slope  of  one-tenth  from  the  edge  of  the  stone 
pitching,  for  10  meters  back  from  this  crest,  with  a stone  flagging 
prolonged  by  a belt  of  puddled  clay  from  0.25  to  0.30  meter  thick. 


676 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


At  30  meters  from  the  edge  a turf  banquette  1.50  meters  high  formed 
the  last  barrier  to  the  water.  Finally  a masonry  berme  10  meters 
wide  was  constructed  at  the  foot  of  the  dike,  following  the  declivity 
of  the  beach.  Thus  reconstructed,  the  dike  has  resisted  the  most 
violent  storms. 

(180)  Dredging  of  the  channel. — The  work  of  deepening  the  outer 
channel  was  carried  on  at  first  by  a Dutch  company,  and  then  by  the 
Fives-Lille  Company.  The  quantity  extracted  at  the  end  of  1888  by 
both  companies  was  1.472,933  cubic  meters,  and  the  price  last  paid 
was  0.92  francs  per  cubic  meter,  raised  and  carried  1 mile.  A careful 
study  of  the  plan  of  the  soundings  made  from  month  to  month 


Fiq.  110.— Cross  section  of  the  wall  of  the  northeast  quay  of  the  outer  harbor. 

during  the  last  seven  years  shows  that,  by  dredging  out  annually 
170,000  cubic  meters,  the  outer  and  inner  channels  may  be  maintained 
at  a depth  of  4 meters  below  datum;  this,  at  the  price  of  0.92  francs 
per  cubic  meter,  amounts  to  85,000  francs. 

(181)  The  sluicing  lock,  which  serves  to  discharge  the  water  accu- 
mulated in  a basin  of  90  hectares  area,  has  five  openings,  each  0 me- 
ters wide,  separated  by  piers  3.50  meters  thick.  The  wetted  peri- 
meter of  these  openings  has  been  arranged  so  that  a discharge  of 
1,000,000  cubic  meters  can  take  place  in  an  hour  under  a head  vary- 
ing from  0 to  4T  meters. 


CIVIL  ENGINEERING,  ETC. 


677 


(182)  Outer  harbor  quays. — The  northeast  quay,  570  meters  long, 

shown  in  section  by  N Fig.  109,  is  for  the  Calais  and  Dover  mail 
steamers.  The  station  and  lines  of  the  Northern  Railroad  Company 
are  placed  here.  • 

The  quay  wall  is  nearly  vertical  and  flush,  except  that  at  equal 
distances  along  it  there  have  been  made  four  recesses  55  meters 
long  and  from  8 to  9 meters  deep.  In  .these  recesses  the  iron  landing 
stages  are  arranged  in  three  stories,  for  the  landing  and  embarkation 
of  passengers  and  freight.  The  two  central  recesses,  which  are 
opposite  the  railroad  station,  are  120  meters  long;  the  others  100; 
the  rest  of  the  quay  may  be  used  for  a fifth  steamer,  or  for  the 
dredges  and  tugs  belonging  to  the  port. 

The  plane  portion  of  the  wall  between  each  recess  has  a uniform 
section  of  7 meters  thick  at  the  base  and  2.70  meters  at  the  top. 
The  foundations  are  sunk  to  the  reference  — G.25  meters,  that  is,  2.75 
meters  below  the  bottom  of  the  outer  harbor,  and  the  total  height  is 
15.75  meters.  Near  the  base  the  face  of  the  wall  is  vertical  ; above 
it  has  a batter  of  one-tenth.  The  thickness  of  the  vertical  portion 
is  7 meters,  but  above  it  is  reduced  by  steps  as  shown  in  Fig.  1 10. 

At  the  right  of  the  landing  stage  the  total  thickness  of  the  wall 
is  13.75  meters  for  a length  of  04  meters:  in  this  wall  two  recesses 
are  made,  each  22.50  meters  long  and  separated  by  a wall  10  meters 
thick.  The  bottom  of  each  recess  slopes  slightly  to  keep  it  clear  of 
water.  The  depth  of  the  lower  is  8.95  meters,  and  that  of  the  upper 
8.20  meters.  The  quay  is  formed  of  two  parallel  walls;  the  outer, 
an  extension  of  that  of  the  quay  and  4 meters  thick,  comes  up  to 
the  level,  2.25  meters;  the  other,  4.50  meters  thick,  extends  to  the 
top  of  the  quay;  the  two  walls  are  connected  by  an  archway  par- 
allel to  the  quay.  The  second  wall,  hollowed  out  behind  by  little 
arches,  contains  a staircase  between  the  middle  and  upper  landings. 

Each  landing  stage  is  formed  of  six  frames  perpendicular  to  the 
face  of  the  wall,  which,  with  the  lateral  walls,  carry  the  floor  beams 
of  the  middle  and  upper  landings.  Each  frame  consists  of  three 
uprights,  one  inclined  and  the  other  two  vertical ; the  bases  of  the 
two  latter  rest  upon  iron  plates  imbedded  in  the  masonry;  the 
columns  are  stiffened  by  cross  braces.  These  columns  support  the 
middle  deck,  and  the  upper  deck  is  supported  in  a similar  manner,  as 
shown  in  Fig.  109-N. 

(183)  The  southwest  quay  (S,  Fig.  109)  is  reserved  for  the  use  of 
the  ocean  steamers  calling  at  Calais.  It  has  a depth  of  7 meters 
below  low  tide  ; the  foundations  were  sunk  to  a reference  — 10  meters  ; 
its  coping  is  +9  meters,  and  its  total  height  19  meters.  This  founda- 
tion was  accomplished  in  a special  manner,  which  will  now  be  ex- 
plained. 

(184)  Foundation  of  the  northeast  and  southwest  quays  of  the  order 
harbor. — The  width  of  the  foundation  was  7 meters ; to  make  a 


i 


C78 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


trench  7 meters  wide  and  5 meters  deep  in  the  fine  sand  and  lay  the 
quay  walls  inside  required  the  construction  of  a costly  cofferdam, 
and  even  then  the  results  were  not  absolutely  sure.  The  method  by 
compressed  air  was' equally  expensive  but  surer. 

After  some  very  successful  experiments  it  was  decided  to  apply, 
for  sinking  the  masonry  curbs  7 meters  by  6.50  and  5 meters  high, 
the  process  so  successfully  used  in  driving  the  wooden  piles  at  Calais. 

These  curbs  were  placed  side  by  side.  The  exterior  walls  are 


vertical,  the  interior  walls  are  vertical  for  a distance  of  6.50  meter. 
They  are  1 meter  thick,  and  are  shown  in  Figs.  Ill  to  113.  The 
base  is  of  concrete  made  in  a mold,  which  is  taken  off  when  the  con- 
crete is  set ; the  rest  is  built  up  of  masonry  laid  in  cement.  The 
blocks  thus  formed  (PI.  VI)  are  not  sunk  until  ten  days  after  they  are 
finished.  This  operation  consists  in  exposing  the  sand  beneath  the 
block  to  the  action  of  powerful  water  jets,  thus  throwing  a mixture 
of  water  and  sand  from  without  into  the  cavity 
within,  and  pumping  the  mixture  of  sand  and 
water  thus  obtained  in  the  middle  of  the  curb. 
For  this  purpose  a centrifugal  pump,  driven  by 
a portable  engine  of  10-horse  power,  was  em- 
ployed; the  suction  pipe  was  suspended  from  high 
scaffolding,  the  orifice  being  placed  a little  below 
the  level  of  the  bottom  of  the  block.  Four  direct- 
acting  force  pumps  were  used  to  drive  the  water 
into  the  sand,  each  pump  throwing  600  liters  per  minute,  with  a 
pressure  of  2 kilograms,  through  three  nozzles  connected  to  the 
pump  by  India  rubber  hose,  which  passed  over  a light,  portable 
staging  above  the  curb. 

The  whole  plant  was  mounted  on  four  platform  cars  and  ran 
upon  rails  laid  parallel  to  the  face  of  the  quay. 

Plate  VI  shows  the  general  arrangement,  and  Fig.  1 II  shows  the  ar- 
rangement of  the  twelve  jets.  Eight  of  them  were  arranged  around 
the  sides  of  the  octagonal  opening,  and  the  four  others  around  the 
suction  pipe  of  the  centrifugal  pump.  Three  of  these  played  around 
the  mouth  of  the  suction  pipe  diluting  the  sand,  augmenting  the 
efficiency  and  diminishing  the  danger  of  choking.  The  twelfth  pipe 
was  united  to  the  suction  pipe,  into  which  it  discharged  just  above 


Fig.  114. — Arrangement 
of  the  jets. 


Paris  Exposition  of  1889 — Vol.  3. 


CONSRTUCTION  OF  THE  OUTER  HARBOR  QUAYS  AT  CALAIS.  PROCESS  OF 


■IKING  THE  MASONRY  FOUNDATION  CURBS  BY  MEANS  OF  JETS  OF  WATER. 


9 


CIVIL  ENGINEERING,  ETC. 


07!) 

its  lower  extremity.  This  arrangement,  devised  by  Mr.  Delanoy, 
kept  the  pump  clear.  The  jets  from  the  nozzles,  all  working  simul- 
taneously, mixed  the  sand  and  water  together,  and  this  mixture  was 
drawn  out  by  the  centrifugal  pump.  Care  was  taken  during  the  op- 
eration that  the  quantity  of  water  forced  in  should  be  the  same  as 
that  pumped  out,  so  that  the  level  of  the  water  in  the  curb  should  bo 
just  below  the  ordinary  level  of  the  water  in  the  surrounding  sand. 
In  this  way  there  was  no  danger  of  the  sand  on  the  outside  caving 
in,  and  only  a quantity  of  sand  not  much  greater  in  bulk  than  that 
of  the  curb  was  taken  out. 

As  one  of  these  blocks  sank,  two  spirit  levels  were  placed  upon  the 
top,  by  which  it  was  easy  to  see  whether  it  was  sinking  vertically, 
and  if  it  was  not,  it  was  regulated  simply  by  lowering  or  raising 
nozzles  on  one  side  or  the  other  so  as  to  force  it  more  or  less  into  the 

sand. 

When  the  curb  had  reached  the  bottom,  after  a descent  of  4 or  b 
meters,  the  sand  was  allowed  to  settle  and  the  opening  was  tilled 
with  hydraulic  bdton.  This  layer  when  hardened  formed  a tight 
tamp,  which  resisted  the  under  pressure  of  the  water  ; the  empty 
space  was  then  pumped  out  and  filled  with  bdton  cement  up  to  the 
level,  where  it  could  be  tilled  with  masonry. 


Fig.  116. — Method  of  cementing  two  con- 
secutive blocks  together. 


The  method  adopted  for  the  whole  work  was  as  follows:  A general 
plan  was  prepared  indicating  the  dimensions  and  position  of  each 
curb,  with  a space  of  0.40  meter  between  each,  which  is  to  be  tilled 
afterwards.  The  positions  of  the  curbs  were  then  marked  out  on 

the  ground. 

Experiments  had  shown  that  in  sinking  such  a row  of  foundations, 
if  every  alternate  curb  was  sunk,  the  condition  of  the  intermediate 
ground  was  unaffected.  The  work  was  begun  by  sinking  all  the 
curbs  numbered  1,  3,  5,  etc.,  and  then  those  numbered  2,  4,  0,  etc., 
until  all  were  sunk.  The  curbs  wei’e  none  of  them  filled  until  all 
were  in  place,  in  order  to  avoid  any  trouble  which  might  arise  from 
the  displacement  of  the  sand  under  the  foundations.  When  all  the 
curbs  were  sunk  they  were  filled  and  then  these  consecutive  blocks 
were  cemented  together,  as  follows:  On  the  front  and  back  of  the 
blocks  iron  plates  (Fig.  116)  were  sunk  down  to  the  foundations  by 
means  of  water  jets.  These  plates  closed  the  space  between  two 


680 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


consecutive  blocks,  the  sand  between  the  blocks  was  then  cleared 
out  by  the  nozzles  and  pump,  and  the  space  filled  with  beton,  made 
of  hydraulic  mortar. 

Upon  the  blocks  thus  united  together  the  foundation  of  the  wall 
was  built  in  masonry  laid  in  Portland  cement.  PI.  VI  shows  this 
whole  operation. 

The  facility  with  which  these  blocks  were  sunk  permitted  the  en- 
gineers in  charge  to  augment  the  dimensions  of  the  blocks  for  the 
foundation  of  the  southwest  quay,  as  well  as  the  depth  to  which  they 
were  sunk.  They  were  8 meters  square  and  8.75  meters  high,  and 
weighed  800  tons.  These  blocks  were  sunk  with  the  same  accuracy 
as  those  of  smaller  dimensions  for  the  northeast  quay,  but  some  diffi- 
culty was  experienced  in  cementing  the  blocks  together,  on  account 
of  the  water  forcing  its  way  under  the  iron  plates.  The  time  of  sink- 
ing the  small  blocks  of  the  northeast  quay  to  a depth  of  about  4.50 
meters  varied  from  ten  to  thirty-five  hours,  the  mean  time  was  re- 
duced to  about  twenty-three  hours,  and  the  mean  volume  displaced 
per  hour  was  6.35  cubic  meters. 

The  time  of  sinking  the  larger  blocks,  8 by  8 by  8,  varied  from  22 
to  119  hours,  with  a mean  of  45. 

The  sinking  of  the  still  smaller  blocks,  4 by  4 by  4.45  meters,  was 
relatively  easier,  the  mean  volume  displaced  per  hour  being  12.5 
cubic  meters. 

The  total  length  of  the  quay  walls  of  the  outer  harbor,  constructed 
under  the  shelter  of  the  dikes  between  1884  and  1888,  is  770  meters. 
The  corresponding  expense  in  round  numbers  was  2,750,000  francs, 
including  the  plant.  The  expense  of  sinking  the  curbs  was  99,000 
francs.  This  expense  corresponds  to  a total  volume  displaced  of 
31,253  cubic  meters,  which  makes  the  cost  3.17  per  cubic  meter  of 
sand  extracted  and  masonry  put  in  its  place.  The  cost  of  removing 
the  sand  between  the  sunken  blocks  and  replacing  it  with  beton  was 
27,540  francs,  thus  bringing  up  the  total  cost  of  sinking  the  solid 
walls  to  3.84  francs  per  cubic  meter,  including  the  labor  and  the 
cost  of  the  plant. 

(185)  Eastern  dock  locks. — The  communication  between  the  outer 
harbor  and  the  eastern  dock  is  established  by  two  parallel  locks  of 
the  same  length  but  unequal  widths.  The  larger  has  a clear  width 
of  21  meters.  The  level  of  the  lowest  part  of  the  invert  is  1.75  meters 
below  the  zero  of  the  charts.  Gate  chambers  are  formed  in  the  ma- 
sonry to  receive  one  pair  of  gates  at  one  end  of  the  lock,  two  pairs 
at  the  other,  and  one  between.  The  maximum  length  of  the  lock 
chamber  is  133.51  meters.  This  length  can  be  divided  in  two  parts, 
which  are,  respectively,  57.50  meters  and  76  meters,  by  means  of  the 
intermediate  gates.  The  smaller  lock  is  similar,  and  has  a width  of 
14  meters.  On  the  left  side  of  these  locks  two  arched  longitudi- 
nal culverts  are  made;  one,  2.10  meters  wide  and  3.60  meters  high, 


G81 


CIVIL  ENGINEERING,  ETC. 

• 

forms  the  prolongation  of  the  culvert  of  the  western  quay  upon  the 
dock,  and  is  intended  to  carry  off  the  flood  water  from  the  Calais 
canal,  the  water  from  the  dry  dock,  and  that  from  the  boat  locks. 

(18G)  Culverts  for  filling  and  emptying  are  also  placed  in  the  cen- 
tral pier  and  in  the  chamber  wall  on  the  right  side  of  the  smaller 
lock.  The  first  is  2.20  meters  wide,  the  second  1.60  meters  wide,  and 
the  height,  3 meters,  is  the  same  in  both. 

Communication  is  made  between  these  outlets  and  the  locks  by 
transverse  branches,  and  the  flow  of  the  water  regulated  by  valves 
and  sluices. 

(186)  Lock  gates. — Each  leaf  is  12.25  meters  wide,  9.80  meters  high, 
and  1.10  meters  thick  for  the  flood  and  1.30  for  the  ebb  gates.  The 
iron  frame  consists  of'eight  horizontal  girders,  spaced  from  1.34  to 
1.36  meters,  connected  at  the  ends  with  two  uprights,  and  having 
four  intermediate  standards  2.32  meters  apart. 

The  leaves  rest  on  pivots  at  the  bottom,  and  at  the  top  they  are 
held  by  iron  trunnions  passing  through  collars  anchored  in  the 
masonry. 

The  14-meter  lock  is  furnished  with  gates  similar  in  all  respects  to 
those  just  described.  The  total  weight  of  each  leaf  is  85  tons  for 
the  larger  and  5(H  for  the  smaller  lock. 

(187)  Turning  bridges. — Four  turning  bridges  are  constructed 
across  these  locks  to  provide  for  the  public  traffic,  two  at  the  lower 
end  and  two  at  the  upper.  They  are  of  similar  construction,  and 
differ  only  in  length,  47.13  and  35.80  meters.  Each  bridge  has  an 
iron  superstructure  and  a double  wooden  flooring.  It  consists  of  a 
single  span  turning  on  a pivot  set  in  the  lock  wall. 

The  framework  of  each  bridge  consists  of  two  main  girders  resting 
on  the  ends  of  a box  girder,  and  united  by  cross-ties,  which  are 
themselves  connected  under  the  flooring  by  stringers.  The  foot  path 
is  carried  on  brackets  mounted  on  the  outside  of  the  main  girders, 
which  have  the  form  of  a parabola  above  and  below.  The  height  of 
each  girder  is  3.30  meters  at  the  right  of  the  box  girder  and  2.70 
meters  at  the  ends. 

When  one  of  the  bridges  is  in  use  it  rests  upon  the  center  pivot, 
and  also  on  three  locking  brackets,  one  at  the  end  of  the  span, 
another  near  the  pivot,  and  a third  at  the  breach,  or  tail  end. 

When  the  bridge  is  opened  the  locking  brackets  are  withdrawn 
and  the  superstructure  rests  principally  upon  the  pivot  and  partially 
on  the  breach  rollers.  During  the  rotation  the  rollers  bear  a maxi- 
mum load  of  5 tons  and  roll  on  a cast-iron  track. 

The  total  weight  of  the  superstructure  of  one  large  bridge  is  265 
tons,  including  counterpoise  of  45  tons  placed  in  the  breach,  used 
to  tilt  the  bridge,  so  as  to  set  free  the  supports.  The  weight  of  one 
of  the  smaller  bridges  is  190  tons,  including  the  counterpoise  of  30 
tons. 


682 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


188.  Apparatus  for  handling. — The  sluices,  gates,  bridges,  cap- 
stans, etc.,  are  moved  by  hydraulic  power  distributed  from  a central 
station  erected  near  the  lock. 

The  green  heart  wood  sluices  slide  in  grooves  cut  in  the  granite 
facing  of  the  polished  walls.  The  lock  gates  are  opened  and  closed 
by  hydraulic  presses  and  tackle;  two  presses  for  each  leaf  placed  side 
by  side,  one  for  opening  and  the  other  for  closing  the  gates.  The 
opening  and  closing  chains  pass  over  two  pulleys,  one  above  the 
other,  in  the  wall  near  the  heel  post.  They  pass  over  a series  of 
guide  pulleys  attached  to  the  upper  part  of  the  leaf,  and  are  secured 
to  a ring  bolt  in  the  wall.  The  controlling  valve,  worked  by  a hand 
lever,  is  so  arranged  as  to  make  a communication  between  one  of 
the  cylinders  with  the  pressure  main  and  the  other  cylinder  with 
the  exhaust  main.  The  arrangement  of  the  admission  and  exhaust 
ports  is  such  that  it  is  possible  to  vary  at  will  the  relation  between 
the  tension  on  the  chain  in  operation,  and  the  resistance  offered  by 
the  one  which  corresponds  to  the  reverse  movement.  A small 
auxiliary  press,  placed  at  the  end  of  the  closing  cylinder,  forces  the 
closing  piston  to  the  end  of  its  stroke  during  the  process  of  opening 
the  gates,  so  as  to  facilitate  the  unrolling  of  the  slack  of  the  chain 
bet  ween  the  walls. 

By  this  novel  arrangement  the  opening  and  closing  of  the  gates 
can  be  effected  by  one  operator,  who  can  always  hold  the  leaf  in 
either  direction  against  the  force  of  the  waves. 

(180)  The  machinery  for  working  the  turning  bridges  moves  the 
pivot,  arranged  so  as  to  tip  and  rotate  independently,  the  tilting  and 
locking  presses,  and  the  two  rotating  tackle  presses. 

The  pivot  turns  in  a cast-iron  cylinder,  filled  with  glycerine  main- 
tained at  a pressure  of  50  kilograms  per  square  centimeter,  upon  a 
circular  lubricated  surface  ; it  carries  at  its  upper  part  the  cylindrical 
rolling  joint  which  serves  for  the  tilting. 

The  tilting  presses  act  by  vertical  plungers  placed  under  the 
principal  girders  of  the  breech. 

When  the  bridge  is  raised  by  the  tilting  presses  the  locking  presses 
throw  on  or  off  the  breech  brackets  which  support  the  bridge  when 
it  is  in  use. 

The  chains  are  coiled  around  an  iron  drum  placed  under  the  super- 
structure on  a level  with  the  supporting  box -girder. 

Four  1-ton  capstans  are  placed  along  each  of  the  outer  sides  of  the 
lock  ; three  others  of  5 tons,  and  two  of  1 ton,  are  arranged  on  the 
central  wall  between  the  two  locks  for  hauling  the  vessels.  These 
capstans  are  driven  by  small  three-cylinder  hydraulic  engines  so  ar- 
ranged that  they  can  be  worked  by  hand  if  the  water  gives  out. 
They  are  so  placed  that  they  can  be  utilized  for  opening  the  gates 
or  turning  the  bridges  in  case  the  accumulator  gives  out,  and  in 
such  a case  a hand  pump  specially  constructed  serves  to  work  the 
sluices  and  the  tilting  presses. 


CIVIJ.  ENGINEERING,  ETC 


688 


The  central  hydraulic  machinery  which  supplies  the  water  under 
pressure,  for  working  the  presses  which  have  been  described,  is 
contained  in  a building  situated  to  the  north  of  the  locks.  It  consists 
of  two  groups  of  pumps,  each  driven  by  a 50  horse-power  engine,  and 
two  accumulators  of  730  liters  capacity  each. 

The  machinery  is  sufficiently  powerful  to  supply  the  Chamber  of 
Commerce  with  water  under  pressure,  and  to  drive  other  hydraulic 
machinery  situated  on  the  quays. 

The  applications  of  hydraulic  power  above  described  are  due  to 
M.  Barret,  engineer  of  the  Marseilles  docks,  who  prepared  the  plans, 
which  were  carried  out  by  the  Fives-Lille  Company  under  the  direc- 
tion of  the  engineers  of  the  port. 


(190)  The  quay  walls  of  the  eastern  dock  have  a total  length  of 
1,505  meters.  These  walls  rest  on  abdton  foundation  2 meters  thick, 
carried  down  to  a depth  of  —3.75  meters.  The  normal  profile  of  the 
walls  has  a height  above  the  foundation  of  10.25  meters  and  a thick- 
ness of  5.80  meters  at  the  base  and  2.50  meters  at  the  top.  This  dif- 
ference in  thickness  is  obtained  on  the  outside  by  a batter  of  one  to 
ten,  followed  by  a curved  face  of  8 meters  radius,  and  on  the  land  side 
by  a series  of  steps  0.37  meter  wide;  (See  Fig.  117).  In  the 
smaller  basin  beyond,  where  the  height  of  the  wall  is  only  7.75  me- 
ters, the  thickness  is  reduced  to  4.20  meters  at  the  base  and  2 at  the 


1 1 1 1 1 

• O I 9 3 4 5 \f 


9 5 4 5 M 


Fig.  117.— Profile  of  the  wall  of  the  eastern  dock. 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


684 

top.  Those  profiles  are  modified  for  the  western  quay,  on  account  of 
a culvert  2.10  meters  wide  and  3.60  meters  high,  placed  at  the  back 
and  used  for  carrying  off  the  flood  waters  of  the  Calais  Canal  into 
the  outer  harbor,  as  well  as  the  water  from  the  dry  dock  and  the  boat 
locks. 

(191)  Foundations. — The  width  of  the  foundation  upon  which  the 
walls  rest  is  6.30  meters.  It  consists  of  a mass  of  bdton  sunk  to  a 
depth  of  2 meters  within  a coffer  dam  formed  of  piles  and  sheet  pil- 
ing. The  dimensions  of  the  piles  were  0.30  by  0.25  by  4.50  meters 
in  length;  the  planks  forming  the  sheet  piling  were  0.10  meter 
thick. 

The  estimated  cost  of  these  coffer  dams  was  450,000  francs.  The 
application  of  the  water  jet  process  enabled  these  dams  to  be  con- 
structed not  only  in  very  much  less  time  than  had  been  estimated, 
but  reduced  the  cost  to  160,000  francs,  thus  realizing  an  economy  of 
290,000  francs. 

This  economy  resulted  not  only  from  the  diminished  cost  of  sink- 
ing the  piles  and  sheet  piling,  but  by  allowing  the  use  of  smaller 
piles  and  thinner  planks.  PI.  V shows  the  operation  of  sinking  the 
piles. 

The  total  cost  of  constructing  the  quay  walls  of  the  dock  and  the 
innet  basin  was  4,000,000  francs. 

(192)  The  western  quay  is  specially  reserved  for  handling  and 
storing  valuable  merchandise  which  has  to  be  protected  against 
the  weather,  and  which  is  only  allowed  to  remain  a very  short  time. 
It  is  provided  with  railways  and  sheds.  The  normal  width  of  the 
quay  is  100  meters,  divided  as  follows: 

First.  An  open  zone  11.50  meters  wide  extending  the  whole  length 
of  the  quay,  carrying  a track  for  hydraulic  traveling  cranes,  and  two 
other  tracks  for  freight  traffic. 

Second.  A zone  of  48  meters  wide,  including  a great  central  hall 
40  meters  wide  formed  by  two  parallel  roofs  each  20  meters  wide, 
and  two  exterior  awnings  each  4 meters  wide. 

Third.  A collection  of  five  tracks,  one  placed  under  the  awning 
next  to  the  dock,  the  remaining  four  occupying  an  uncovered 
space  18  meters  wide.  The  track  standing  nearest  the  sheds  is  used 
chiefly  as  standing  room  for  wagons  to  be  loaded  or  unloaded. 
The  four  others  serve  as  sidings  for  full  or  empty  cars  and  the  mak- 
ing up  and  dispatching  of  trains. 

Fourth.  A paved  road  16.50  meters  wide,  including  space  for  a 
track  which  will  subsequently  be  laid  along  the  outer  sidewalk. 

Fifth.  A sidewalk  6 meters  wide  running  along  a series  of  blocks 
for  a depth  of  50  meters  along  the  quay,  to  be  reserved  for  the 
construction  of  stores,  depots,  and  other  establishments  required  for 
a marine  station. 


CIVIL  ENGINEERING,  ETC. 


685 


Beyond  the  quay  proper  the  public  domain  extends  along  a zone 
70  meters  wide,  including  the  belt  of  50  meters  occupied  by  the 
blocks  reserved,  just  referred  to,  and  by  an  outer  street  20  meters 
wide,  upon  which  railway  tracks  will  be  laid  to  accommodate  the 
stores  when  they  are  constructed. 

(195)  The  eastern  quay  is  reserved  for  the  storage  of  a low  class 
of  merchandise,  such  as  wood,  iron,  minerals,  charcoal,  etc.,  which 
can  remain  exposed  to  the  weather  without  damage.  The  total  width 
of  this  quay  is  140  meters,  divided  as  follows: 

First.  Three  lines  for  loading  and  unloading  cars.  The  middle 
line  is  reserved  for  a traveling  crane. 

Second.  An  open  space  G7.50  meters  wide. 

Third.  Five  tracks  occupying  a total  width  of  21  meters. 

Fourth.  A macadamized  road  13  meters  wide. 

Fifth.  A zone  of  10  meters  fenced  in  and  occupied  by  two  branch 
lines  connecting  the  central  Calais  station  with  the  maratime  term- 
inus. 

Sixth.  An  outer  street  15  meters  wide. 

(194)  Hydraulic  cranes. — A system  of  mains  has  been  laid  down, 
starting  from  the  central  hydraulic  station  and  extending  around  the 
dock,  to  supply  the  various  cranes,  etc.,  established  on  the  quay. 
These  include  10  traveling  cranes  of  1,500  kilograms  each,  2 double- 
power traveling  cranes  of  5,000  and  2,500  kilograms,  and  G movable 
winches  of  750  kilograms,  1 fixed  double-power  crane  of  20,000  and 
and  40,000  kilograms. 

(195)  Hie  dry  dock  is  constructed  at  the  southern  extremity  of  the 
eastern  dock,  and  a space  has  been  reserved  alongside  for  the  con- 
struction of  two  similar  docks  when  they  shall  be  required.  An 
unloading  stage  for  timber  occupies  provisionally  the  space  reserved 
for  these  two  docks.  This  work  comprises  three  different  parts — the 
entrance  lock,  the  dock  itself,  and  the  culverts. 

The  entrance  lock  is  21  meters  wide,  like  the  great  lock  of  the 
eastern  dock.  Its  side  walls  have  two  recesses  for  the  reception  of 
the  caisson  gate  which  closes  the  entrance. 

The  dry  dock  has  a total  length  of  141.25  meters  measured  along 
the  flooring  from  the  inner  recess  of  the  caisson  gate  to  the  base  of 
the  rounded  edge.  The  maximum  thickness  of  this  gate  being  4 
meters,  the  useful  length  of  the  dock  is  138.50  or  152  meters,  ac- 
cording as  the  gate  takes  its  bearing  against  the  inner  or  the  outer 
recess.  The  width  of  the  flooring  between  the  bottom  altars  is  9.30 
meters,  including  the  side  draining  channels  which  run  round  the 
floor  of  the  dock. 

The  first  four  altars  starting  from  the  bottom  are  0.35  meter  high 
and  1.30  meters  wide.  The  width  of  the  dock  at  the  level  of  the 
fourth  altar  is  thus  19.70  meters;  a width  requisite  for  the  accom- 
modation of  the  light-draft  paddle  steamers  used  for  the  channel 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


<(‘>86 

service.  From  this  level  to  that  of  the  coping  the  dock  has  two  in- 
termediate steps  1.25  meters  wide,  to  serve  for  shoring,  and  to  facili- 
tate the  passage  of  the  workmen.  The  width  at  the  coping  is  27.40 
meters. 

Several  stairways  are  placed  along  the  walls,  and  a timber  slide  is 
provided  at  the  extremity  of  the  rounded  end. 

A culvert  1.25  meters  wide  and  2.50  meters  high,  opening  into  the 
lower  end  of  the  dock  near  the  inner  recess  of  the  caisson  gate,  is  built 
behind  each  wall,  and  small  transverse  culverts  run  from  it  to  the 
lateral  channels  on  each  side  of  the  flooring.  The  culverts  carry  off 
the  water  to  the  pumping  well  when  the  dock  is  emptied  or  drained. 

The  well  under  the  engines  and  centrifugal  pumps  is  arranged  so 
as  to  serve  in  future  for  the  filling  and  draining  of  the  two  other 
docks  not  yet  built.  The  engines  and  the  pumps  are  calculated  to 
pump  out  the  dock  in  3 hours  at  the  most. 

A set  of  small  centrifugal  pumps  serve  to  keep  the  dock  clear  while 
in  use. 

The  great  pumps  are  driven  by  belting  from  two  upright  engines 
which  together  develop  800  horse  power. 

The  cost  of  constructing  the  dock  amounts  in  round  numbers  to 
2,700,000  francs 

(196)  The  barge  dock  forms  the  prolongation  and  end  of  the  Calais 
Canal,  and  communicates  on  the  eastern  side  with  the  eastern  dock 
and  on  the  west  with  the  old  port.  The  flooring  is  placed  at  the  ref- 
erence 1.95  meters,  that  is  to  say,  2.80  meters  below  the  normal  level 
of  the  canal  (4.75  meters).  The  boats  never  draw  more  than  1.80 
meters. 

The  quay  walls  of  this  dock  are  of  solid  masonry,  set  in  hydraulic 
cement  upon  a bed  of  bdton  0.70  meter  thick.  The  height  of  the  wall 
is  4.45  meters;  its  thickness  varies  from  2 meters  at  the  base  to  1.10 
meters  at  the  top,  with  a batter  of  one-fifth  or  one-sixth. 

Two  locks  connect  the  eastern  branch  of  this  dock  with  the  new 
eastern  dock;  they  are  38.50  meters  long  and  6 wide,  separated  by  a 
wall  7 meters  thick.  The  gates  are  of  oak  and  worked  directly  by 
hydraulic  pressure. 

(197)  The  guard  lock  is  built  at  the  lower  end  of  the  western  branch 
of  the  boat  basin,  and  is  arranged  so  as  to  form  a dam  either  against 
the  sea  or  against  the  canal.  Its  gates  must  not  only  be  able  to  resist 
the  pressure  of  the  water  in  both  directions,  but  they  should  also  be 
capable  of  being  opened  and  closed  against  the  stream,  whatever  may 
be  the  direction  or  the  velocity  of  the  current.  The  length  of  the 
lock  is  26  meters,  and  its  clear  width  7;  it  is  closed  by  two  pairs  of 
miter  gates,  each  of  which  consists  of  two  vertical  wings  of  unequal 
width  united  to  the  same  heelpost.  When  these  are  closed  they  form 
an  angle  slightly  less  than  a right  angle;  when  the  lock  is  open  each 
wing  comes  into  its  appropriate  curved  recess — in  plan  the  quadrant 


* 


CIVIL  ENGINEERING,  ETC. 


687 


of  a circle — formed  in  the  side  wall  of  the  lock,  and  corresponding 
in  shape  to  that  of  the  gate. 

The  lock  is  closed  when  the  narrower  wings  of  the  gates  are 
brought  together  against  the  miter  sill.  In  opening  and  closing,  the 
second  wing  of  each  leaf  remains  within  the  curved  recess,  in  which 
it  moves  with  a slight  play  between  itself  and  the  curved  wall.  On 
each  side  of  the  lock  are  two  separate  culverts,  starting  from  the  lock 
head  and  tail  and  emptying  into  the  curved  recesses  above  referred 
to.  These  culverts  can  be  opened  or  closed  at  will  by  a system  of 
sluices,  in  such  a manner  that  the  pressure  of  the  water  discharged 
from  them  can  be  exerted  against  the  exterior  face  of  the  wider 
wing  of  the  leaf,  at  the  head  or  tail  end,  whenever  there  is  a differ- 
ence of  level  at  the  two  ends  of  the  lock.  If  the  culvert  communi- 
cating with  the  lower  end  is  closed,  the  gates  will  shut  themselves 
if  the  direction  of  the  fall  is  from  the  upper  to  the  lower  end.  If 
this  state  of  things  is  reversed,  the  sluice  controlling  the  upper  end 
of  the  culvert  must  be  closed  and  that  at  the  lower  end  opened. 

Five  bridges  have  been  constructed  over  the  Calais  Canal  and 
barge  dock  to  maintain  the  railroad  and  boat  communications. 

(198)  Cost. — The  cost  of  the  boat  basin  was  as  follows  : 


Francs. 

Earthwork  and  masonry 3, 800, 000 

Lock  gates  and  apparatus 290, 000 

Bridges 310,000 


4, 400, 000 

The  designs  of  the  works  above  described  were  prepared  under 
the  direction  of  MM.  Stoecklin.  Plocq,  and  Guillain,  chief  engineers, 
and  M.  Vdtillart,  engineer  of  the  port  of  Calais. 

I wish  to  acknowledge  my  special  obligations  to  M.  Vdtillart  for 
descriptions  and  photographs. 

Chapter  XIX. — The  new  outer  harbor  at  Boulogne. 

(199)  The  situation  of  the  port  of  Boulogne  in  1878,  when  it  was 
decided  to  make  a deep  harbor  here,  was  as  follows  : 

A bar  was  formed  near  the  entrance  to  the  jetties,  rising  to  a 
height  of  1 meter  above  the  zero  of  the  charts.  The  entrance  to  the 
interior  channel,  between  two  jetties  70  meters  apart,  exposed  to  all 
the  winds  from  the  west,  was  inaccessible  at  high  tide  for  ships  draw- 
ing more  than  5 meters. 

The  bottom  of  the  inner  harbor,  with  a surface  of  13  hectares,  was 
3 meters  above  zero.  The  dock,  accessible  through  a lock  21  by  100 
meters,  and  having  a surface  of  G.87  hectares,  had  its  bottom  0.60 
meter  above  zero. 


688 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


The  difficulties  of  access  and  the  insufficient  depth  in  the  channel 
prevented  this  dock  from  doing  its  full  service. 

Notwitstanding  all  these  difficulties  the  annual  tonnage  exceeded 
983,000  tons,  the  number  of  passengers  was  130,000,  and  the  duties 
collected  exceeded  7,500,000  francs. 

(200)  Project  for  a deep-water  harbor. — There  was  a littoral  cur- 
rent of  3 knots  per  hour  in  front  of  the  port  between  the  two  rocky 
points  of  Heurt  and  Creche,  where  the  sand  was  always  washed 
away  but  no  shoal  made.  If,  therefore,  a breakwater  8 or  9 meters 
deep  be  erected  from  north  to  south,  through  shoals  parallel  to  the 
direction  of  the  current,  and  in  a line  with  these  two  points,  it  will 
be  exposed  to  erosion  rather  than  to  silting.  If  this  breakwater  be 
connected  with  the  coast  at  its  two  extremities,  and  a principal  en- 
trance reserved  toward  the  west,  this  pass  will  preserve  its  depth 
and  no  serious  disturbance  will  be  made  in  the  regime  of  the  coast. 


Fig.  118.— Plan  of  the  port  of  Boulogne  : a,  the  southwest  dike  ; b , the  (like  parallel  to  the  coast ; 
c,  the  isolated  mole  ; d,  the  northeast  dike.  The  Liane  River  Hows  through,  m,  the  storage  basin, 
s.  the  inner  basin,  r,  the  inner  harbor,  then  out  through  the  jetties  S. 

The  port  thus  formed  will  be  in  no  danger  of  silting  up.  The  proj- 
ect of  M.  Stoecklin,  prepared  according  to  the  above  principles,  is 
represented  in  Fig.  118. 

It  consisted  in  making,  in  front  and  to  the  south  of  Boulogne,  a new 
harbor  nearly  rectangular  in  shape,  with  an  area  of  300  hectares,  hav- 
ing two  passes  open  to  a depth  of  8 meters  at  low  tide;  in  the  interior, 
landings  and  quays  are  built,  accessible  at  all  times  for  steamers 
drawing  5 meters  of  water. 

(201)  The  perimeter  of  this  harbor  is  formed  of  three  dikes,  one 
parallel,  and  the  others  nearly  at  right  angles  to  the  shore.  The  first 
has  a total  length  of  1,100  meters  divided  into  two  portions  by  an 
intermediate  pass,  called  the  western  pass,  250  meters  wide.  The 
north  branch,  c,  comprised  between  the  west  pass  and  the  north  pass 


CIVIL  ENGINEERING,  ETC. 


689 


which  separates  it  from  the  northeast  jetty,  d,  is  to  form  a mole  500 
meters  long,  and  separated  from  the  land.  The  southern  branch,  b, 
600  meters  long,  unites  with  the  southwestern  dike  a by  a curve  of 
350  meters  radius.  This  last  dike  is  nearly  perpendicular  to  the 
shore,  where  it  is  united  with  the  rocks.  It  is  1,650  meters  long,  in- 
cluding the  curved  portion. 

The  northeast  dike,  d,  whicli  completes  the  inclosure,  is  the  pro- 
longation for  1,440  meters  of  the  actual  northeast  jetty.  Its  north- 
west extremity  is  separated  from  the  isolated  mole  by  the  north  pass, 
150  meters  wide.' 

(202)  The  object  of  the  proposed  improvements  was  as  follows: 

First.  To  furnish  a harbor  of  refuge  for  the  fishermen  and  coasters. 

Second.  To  facilitate  the  access  to  the  inner  harbor  by  protecting 

the  entrance  into  the  channel  against  the  waves  at  all  times,  and  pro- 
viding approaching  vessels  with  a shelter  where  they  could  await  in 
security  a favorable  time  and  tide. 

Third.  To  provide  quays  accessible  at  all  times  for  channel  steam- 
ers as  well  as  for  coasters  and  fishing  vessels. 

(203)  Work  done  from  1879  to  1889. — The  work  began  in  July, 
1879.  At  the  foot  of  the  abrupt  cliffs  bordering  on  the  sea  between 
Boulogne  and  Portel  they  built  two  wharves,  having  a surface  of  7 
hectares  included  between  two  retaining  walls,  and  these  wharves 
were  connected  by  a road  with  the  city,  and  by  a railroad  with  the 
northern  railroad  station.  Quarries  were  opened  at  the  foot  of 
Portel  cliffs  and  united  with  the  wharves  by  inclined  planes.  They 
then  constructed  a little  haven,  included  between  the  shore  end  of 
the  southwest  dike  and  two  jetties  100  meters  and  270  meters  long, 
to  facilitate  the  loading  of  the  materials  intended  to  form  the  sub- 
structure of  the  proposed  dikes.  It  was  only  after  these  first  works 
were  finished  that  they  could  proceed  with  the  construction  of  the 
dikes.  The  part  of  the  inclosure  of  the  deep-water  harbor  already 
finished  includes  the  branches  a and  b.  These  two  branches  consti- 
tute in  reality  one  and  the  same  jetty,  a beginning  perpendicular  to 
the  coast,  b parallel  with  it,  and  the  two  united  by  the  arc  of  a circle 
of  350  meters  radius.  (Fig.  119). 

This  jetty,  which  forms  a breakwater  in  the  direction  of  the  south- 
west and  west,  begins  at  a point  on  the  coast  between  Boulogne  and 
Portel,  at  1,750  meters  to  the  south  of  the  actual  entrance  to  the  har- 
bor. Its  total  length  is  2,110  meters,  including  1,265  meters  for  the 
dike  a from  its  beginning,  360  meters  for  the  curve,  and  485  meters 
for  b. 

The  profile  of  the  dike  consists  of  two  distinct  parts  corresponding 
to  the  substructure  and  the  superstructure.  The  substructure  is 
formed  by  a mass  of  natural  and  artificial  riprap,  composed  of  a 
central  core  of  stones  weighing  100  kilograms  apiece,  resting  on  the 
bottom  and  rising  to  a level  of  1 meter  above  low  tide.  The  slopes  of 
H.  Ex.  410— vol  in 44 


C90 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


CIVIL  ENGINEERING,  ETC 


691 


this  first  mound  are  covered  on  the  shore  side,  for  a thickness  of  2.50 
meters,  by  what  is  designated  as  “rubble  of  the  first  category.”  It 
is  a stone  pitching  made  up  of  rocks  weighing  500  kilograms  each. 
On  the  side  toward  the  sea  the  slope  is  protected,  first,  by  a revet- 
ment of  rubble  work,  made  up  of  rocks  weighing  6,000  kilograms 
apiece,  called  “rubble  of  the  second  category,”  and,  second,  by  bdton 
blocks  of  uniform  dimensions  weighing  33  tons  each.  (Fig.  120). 

Between  the  references  +2  and  +4  meters  rises  amass  of  masonry 
9 meters  wide,  serving  as  the  foundation  of  the  masonry  wall  which 
constitutes  the  superstructure  of  the  dike. 

The  profile  of  this  wall  is  trapezoidal,  6.90  meters  high,  7.66  me- 
ters wide  at  the  base,  and  6 at  the  top. 

The  upper  platform  rises  to  the  reference  10.90  meters,  that  is,  2 
meters  above  mean  high  water.  It  is  surmounted  by  a parapet  1.40 
meters  high  and  from  2.50  to  2 meters  thick.  On  each  side  of  the 


wall  and  on  a level  with  the  lower  platform  the  slopes  are  consolida- 
ted by  masonry  bermes  formed  of  isolated  blocks,  each  6 meters  long, 
which  serve  to  protect  the  foot  of  the  wall  and  also  afford  a path  for 
the  workmen  and  materials  at  low  tide.  The  thickness  indicated  for 
the  wall  was  adopted  at  a distance  of  1,350  meters  from  the  beginning 
of  the  dike. 

The  width  at  the  top  is  only  4 meters  for  a distance  of  1,120  meters 
from  the  shore  ; then  it  is  made  5 meters  for  a distance  of  1,350. 

All  along  the  curve  which  forms  the  part  of  the  dike  most  severely 
exposed  to  southwest  winds  and  storms  the  width  is  6 meters ; the 
outer  slopes  have  been  loaded  with  several  layers  of  artificial  blocks, 
and  the  exterior  bermes  raised  to  the  reference  of  5 meters.  A 
slope  communicates  between  the  upper  platform  of  the  dike  and  the 
interior  berme,  to  facilitate  the  supply  of  materials  during  the  con- 
struction, and  increase  the  time  of  the  work  for  each  low  tide.  The 
dike  is  terminated  by  a provisional  pier-head  signal,  and  by  a lu- 
minous buoy.  The  field  work  included  a double  organization  corre- 


692 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


sponding  to  liigli  and  low  tides.  The  sinking  of  the  artificial  blocks 
and  the  rocks  for  the  revetment  took  place  at  high  tide.  The  latter 
were  transported  and  sunk  by  means  of  hopper  barges  towed  by  a 
little  steamer ; each  of  these  barges  carried  a weight  of  100  tons. 

The  artificial  blocks  were  unloaded  at  high  tide  by  means  of  a 
special  wrought-iron  barge  having  three  vertical  pits,  with  which  at 
each  trip  of  the  barge  they  could  sink  three  blocks,  but  this  operation 
required  a certain  precision,  and  generally  only  one  trip  could  be 
made  at  each  high  tide. 

The  loading  and  discharge  of  the  riprap  was  possible,  on  the  con- 
trary, with  waves  0.50  meter  high,  which  allowed  the  use  of  more 
than  half  of  the  tide.  At  low  tide  the  stones  required  to  complete 
and  even  up  the  central  core  were  sunk,  as  well  as  a great  portion  of 
the  natural  and  artificial  blocks  which  were  to  form  the  revetment 
of  the  side  slopes.  For  the  heavy  rock  work  they  made  use  of  tip 
wagons  ; for  the  great  blocks  they  employed  tlnee-wheeled  trucks, 
the  platform  of  which  could  be  raised  and  tipped  by  means  of  jacks. 
These  trucks  ran  upon  rails  laid  on  the  bermes  of  the  walls  already 
constructed. 

They  were  able  to  utilize,  at  low  tide,  four-fifths  of  the  number  of 
tides;  during  the  winter  they  could  only  succeed  in  preventing  the 
dispersion  of  the  interior  mass  by  the  action  of  the  waves.  The 
advancement  was  difficult  at  first,  and  to  avoid  the  loss  of  material 
they  were  obliged  to  stop  the  riprap. work  from  November  to  April. 
Experience  showed  that  the  only  way  to  prevent  accidents,  and  to 
extend  and  preserve  the  advancement  attained  during  the  good  sea- 
son, was  to  construct,  as  soon  as  the  platform  emerged  to  a sufficient 
height,  isolated  blocks  of  masonry  which  loaded  and  consolidated 
this  platform.  These  blocks  were  to  make  a part  of  the  bermes  and 
the  foundation  of  the  walls,  but  they  rested  sometimes  as  isolated 
blocks,  and  could  settle  until  they  had  attained  a state  of  stable  equi- 
librium. At  the  end  of  about  a year  the  blocks  situated  in  the  cen- 
tral part  of  the  dike  were  united  so  as  to  form  the  foundations  of  the 
wall.  At  the  moment  of  stopping  work  all  the  joints  exposed  to  the 
waves  were  filled  with  rapid-setting  cement.  When  the  work  recom- 
menced this  mortar  was  removed,  the  joints  were  cleaned,  and  new 
cement  was  placed  on  all  the  parts  against  which  new  masonry  rested. 

The  total  cost,  from  1879  to  1889,  of  the  organization  of  the  works 
and  the  construction  of  the  southwest  and  parallel  dikes  (a  and  b), 
amounts  in  round  numbers  to  14,500,000  francs.  Besides,  1,850,000 
were  expended  in  constructing  the  first  part  of  the  wharf,  and 
2,000,000  were  used  up  in  dredging  in  the  interior  harbor  and  the 
entering  pass. 

(204)  Results  obtained — Improvements  to  be  made. — Although  the 
programme  of  1878  has  not  yet  been  completed  the  following  re- 
sults may  be  considered  as  already  obtained. 


CIVIL  ENGINEERING,  ETC. 


693 


First.  The  entrance  to  the  interior  channel  is  completely  sheltered 
against  the  southwest  winds  and  tempests,  which  are  the  most  fre- 
quent and  violent  in  this  region ; it  is  even  partially  sheltered 
against  the  tempests  and  winds  from  the  west. 

Second.  The  regime  of  the  currents  at  the  entrance  of  the  port  has 
been  completely  modified.  The  current  of  flow  passed  formerly  at 
the  head  of  the  jetties,  at  the  moment  of  high  tide,  with  such  velocity 
during  certain  tides  as  to  render  the  entry  of  the  port  impossible 
for  great  ships ; it  is  carried  to-day  beyond  the  dike  and  is  only  felt 
at  the  entry  of  the  port  as  a feeble  eddy. 

Third.  The  protection  obtained  at  the  entrance  of  the  port  against 
the  waves  and  currents,  has  permitted  the  deepening  of  the  exterior 
pass  and  the  channel,  and  the  maintenance  without  difficulty  of  the 
depths  already  obtained.  These  depths  are  to-day  more  than  4 
meters  below  zero  in  the  exterior  pass,  and  2 meters  between  the 
jetties.  They  are  sufficient  to  allow  the  regular  service  of  steamers 
between  Boulogne  and  Folkestone,  a service  organized  more  than 
three  years  ago. 

Fourth.  The  dike  already  forms  a little  haven  of  50  acres  suffi- 
ciently sheltered  from  the  southwest  and  west  winds,  which  will  be 
of  great  service  as  soon  as  the  dredging  giving  it  a depth  of  6 or  7 
meters  shall  be  finshed. 

With  regard  to  the  modifications  of  the  beaches,  it  may  be  stated 
that  the  anticipations  of  the  authors  of  the  project  are  realized. 
There  is  a tendency  to  erosion  at  the  bottom,  in  front  of  the  paral- 
lel dike,  indicating  that  the  depth  in  the  passes  of  the  harbor  will  be 
kept  in  order  naturally  if  the  primitive  project  is  entirely  realized. 
The  beach  situated  on  the  south  of  the  southwest  branch  has  risen 
notably  in  its  upper  parts,  the  slope  has  become  more  steep,  but  its 
foot  does  not  appear  to  have  changed,  and  the  great  current  which 
follows  the  lateral  branch  will  not  permit  it  to  advance.  On  the 
interior  of  the  harbor,  that  is  to  say,  on  the  north  of  the  dike,  there 
is  a little  silting,  produced  on  account  of  the  calm  obtained,  but,  as 
has  been  foreseen,  this  silting  is  of  no  importance  and  can  easily  be 
removed  by  dredging. 

These  excellent  results  have  allowed  the  completion  of  the  pro- 
gramme of  1878  to  be  adjourned  without  prejudice  to  local  interests. 
The  conditions  of  access  to  the  port  of  Boulogne  are  such  to-day  that 
the  quays  and  wharves  projected  for  the  deep-water  harbor,  always 
accessible  to  the  steamers  and  fishermen,  may  be  carried  to  the  inner 
harbor.  The  deepening  of  the  harbor  and  the  construction  of  the 
new  qiiavs  will  be  immediately  carried  out. 

(205)  As  to  the  construction  of  the  dikes,  it  is  possible  that  when 
the  work  is  recommenced  the  engineers  will  consider  them  useless 
for  the  security  of  the  harbor,  the  complete  closing  of  which  had 
been  originally  planned ; a simple  prolongation  of  the  actual  parallel 


694 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


dike  for  a length  of  500  or  600  meters  will  probably  be  sufficient  to 
assure  an  excellent  shelter  against  great  storms. 

But  the  works  must  be  completed  by  important  dredging,  to  assure, 
over  a sufficient  extent,  the  depth  of  8 meters  requisite  for  ship 
navigation. 

The  project  for  the  deep-water  harbor  at  Boulogne  was  drawn  up 
by  M.  Stoecklin,  general  inspector.  The  works  were  carried  out 
successively  under  the  direction  of  MM.  Plocq,  Cfuillain,  and  Vdtil- 
lart,  chief  engineers,  and  Barreau  and  Mommerque,  assistant  engi- 
neers. 


Chapter  XX. — Port  of  Havre — Bellot  Lock. 

(206)  Bellot  lock. — The  Bellot  basin  for  the  use  of  the  transatlantic 
steamers  connects  with  the  Eure  basin  by  a lock  30  meters  wide. 
The  lock  is  furnished  with  ebb  gates  separating  the  two  basins.  It 
is  crossed  by  a drawbridge  of  a single  span  and  double  track.  Hy- 
draulic capstans  placed  on  each  wing  wall  are  designed  to  facilitate 
hauling  the  ships.  All  the  working  apparatus  is  moved  by  hy- 


Fig.  121.  Transverse  section  of  the  Bellot  lock. 

draulic  power.  The  chamber  walls  of  the  lock  are  vertical,  and 
unite  with  the  invert  by  circular  arcs  of  2 meters  radius ; their 
thickness  is  7.70  meters,  and  the  sill  is  placed  at  the  reference  —2.65 
meters,  which  gives  a draught  of  8.30  meters  at  low  tide. 

(207)  Iron  drawbridge. — The  iron  bridge  just  mentioned  is  53.25 
meters  long — 36  meters  for  the  span,  17.25  meters  for  the  breech,  and 
7.72  meters  wide.  It  consists  of  two  girders  forming  the  parapets, 
with  a variable  height  from  the  extremity  to  the  point  where  the 
tension  is  a maximum.  These  girders  are  united  by  cross  girders 
and  wind  ties.  The  longitudinal  girders  have  a height  of  2. 10  meters 
at  their  extremities,  and  4 meters  at  the  right  of  the  pivot.  They 
are  formed  of  a trellis  of  channel  iron  inclined  at  45  degrees  and 
spaced  0.85  meter  between  the  axes.  The  uprights  divide  the  girder 
into  fourteen  panels  3.40  meters  wide.  The  plate-iron  transverse 
beams  are  80  centimeters  high  and  3.40  meters  apart;  they  rest  on 
the  lower  plate  of  the  side  girders,  and  are  united  by  stringers  placed 


CIVIL  ENGINEERING,  ETC. 


695 


under  the  rails  of  the  railroad  and  under  the  plates  of  the  roadway. 
The  bridge  is  calculated  to  allow  the  passage  on  the  railroad  of  the 
heaviest  locomotives  of  the  Western  Company  (14  tons  per  axle),  or 


the  simultaneous  passage  upon  each  of  the  roadways  of  two  files  of 
carts  weighing  11  tons  per  axle. 


696 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


(208)  Lock  gates. — The  lock  gates  (see  Plate  VII)  are  of  plate  iron, 
each  leaf  1G.515  meters  wide  and  10.90  meters  high.  These  gates 
retain  the  water  in  the  Bellot  basin  at  the  reference  ?.85  meters,  that 


is  to  say,  at  10.50  meters  above  the  level  of  the  invert.  They  are 
calculated  on  the  hypothesis  that  the  level  of  the  water  in  the  Eure 
basin  may  by  some  accident  fall  to  the  zero  of  the  charts.  The  sys- 


Paris  Exposition  of  1889— Vol.  3.  Civil  Engineering,  etc.— PLATE  VII. 


HAVRE.  LOCK  GATES  OF  THE  BELLOT  BASIN 


CIVIL  ENGINEERING,  ETC. 


697 


tem  of  construction  adopted  consists  of  verticals  supporting  the  ex- 
terior skin  and  resting  on  two  horizontal  crossbeams,  one  on  the 
upper  part  and  the  other  on  the  lower.  The  skeleton  consists  of: 

First.  A frame  made  by  an  upper  cross  girder,  a lower  cross  girder, 
and  two  tubular  pits  forming  the  heel  and  miter  posts. 

Second.  Nine  vertical  ribs  spaced  1.393  meters  apart. 

Third.  Two  horizontal  intermediate  girders  to  brace  the  uprights. 

Fourth.  Horizontal  U-shaped  plates  unequally  spaced  and  serving 
to  stiffen  the  skin  which  forms  the  two  faces  of  the  gate. 

The  space  included  between  the  lower  horizontal  girder  and  the 
first  intermediate,  counting  from  below,  constitutes  a series  of  water- 
tight chambers  intended  to  ballast  the  leaf;  the  rest  of  the  space 
included  between  the  lower  horizontal  girder  and  the  second  inter- 
mediate one  forms  air  chambers.  Above  this  second  horizontal  gir- 
der the  compartments  communicate  with  the  water  of  the  Bellot 
basin. 

Two  vertical  water-tight  shafts,  with  manholes  and  ladders  con- 
veniently placed,  afford  access  to  the  different  portions  of  the  gate. 
The  pivot,  which  is  placed  in  the  invert,  is  of  forged  steel.  It  is  the 
same  with  the  upper  pivot  of  the  leaf.  The  anchor  which  serves  as 
the  hub  of  the  pivot  and  which  transmits  to  the  masonry  the  pres- 
sure of  the  leaves,  the  pivot  step,  and  the  two  intermediate  counter- 
forts which  maintain  the  direction  of  the  heel  post  are  of  cast  steel. 
The  anchorage  straps  which  transmit  the  pressure  to  the  masonry 
rest  on  steel  plates  0.0G  meter  thick,  and  are  embedded  in  the  granite 
forming  the  quoin.  The  air  chambers,  which  are  not  sufficiently 
tight  to  avoid  leakage,  are  cleai'ed  by  means  of  compressed  air. 

(209)  Hydraulic  apparatus. — The  Bellot  lock  is  furnished  with 
hydraulic  apparatus  which  works  the  bridge,  the  gates,  the  shiices, 
and  the  hydraulic  capstans.  All  these  pieces  are  worked  by  water 
under  pressure  from  a central  station.  The  pressure  is  52  kilograms 
per  square  centimeter. 

The  general  arrangement  of  the  apparatus  for  operating  the  bridge 
is  as  follows:  The  two  supporting  beams  of  the  bridge  rest  upon 
a box  girder,  which  is  itself  placed  upon  a pivot  contained  in  the 
cylindrical  step  resting  on  a metallic  wedge.  This  wedge,  acted 
on  directly  by  a hydraulic  press,  gives  a vertical  movement  to  the 
cylinder  and  consequently  raises  the  entire  bridge.  (Fig.  126). 

The  advantage  of  this  mode  of  raising  the  bridge  is  as  follows : 
The  pivot  undergoes  no  displacement  with  respect  to  the  cylinder, 
and  a constant  contact  of  the  metallic  surfaces  subsists  through  the 
whole  motion.  A leak  in  the  stuffing  box  would  not,  consequently, 
produce  any  accident,  the  bridge  being  held  by  the  wedge  in  its 
position. 

The  rotation  of  the  bridge  is  effected  by  the  action  of  a pair  of 
twin  pulleys.  To  facilitate  this  motion  and  avoid  the  great  friction 
of  the  metallic  surfaces  in  contact,  the  cylindrical  step  carries  in 


G98 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


its  upper jpart  a stuffing  box,  forming  a tight  joint  between  the  pivot 
and  the  cylinder.  Water  under  pressure,  introduced  in  the  small 
slots  made  in  surfaces  of  contact,  supports  the  bridge  without  rais- 
ing it,  and  effects  the  rotation  upon  the  water  itself. 

The  bridge  when  closed  rests  on  two  supports  upon  each  side  of 
the  chamber  walls  at  its  extremities.  During  the  motion  of  lifting 


it  turns  around  a semicylinder  fixed  under  the  framing,  and  engages 
in  a circular  cavity  made  in  the  upper  part  of  the  pivot.  During  the 
rotation  the  bridge  rests  on  its  pivot,  and  upon  the  breech  rollers, 
which  are  four  in  number,  two  on  each  side.  The  amount  of  water 
used  for  lifting  the  bridge  is  462  liters,  and  for  lowering,  378  liters; 


Fig.  127.— Elevation  and  plan  of  a leaf  of  the  Belot  lock  gates. 


for  turning,  150  liters  when  a partial  power  is  used,  and  292  liters  when 
the  maximum  power  is  used.  This  last  is  regulated  according  to 
the  force  of  the  wind,  which  is  the  principal  obstacle  to  the  motion. 
The  total  quantity  used  for  the  double  operation  of  opening  and 
closing  is  1,140  liters  or  1.340  liters,  according  as  the  greater  or  the 
less  power  is  used.  The  time  required  for  opening  is  two  minutes. 


CIVIL  ENGINEERING,  ETC. 


699 


(210)  The  opening  of  the  gates. — The  apparatus  for  moving  the 
gates  comprises  one  for  opening,  and  another  for  closing  them. 
The  first  consists  of  a cylinder  with  a plunger  forming  a pulley;  the 
second  is  identical,  with  the  single  difference  that  the  cylinder,  in- 
stead of  having  a simple  plunger,  is  furnished  with  a piston  which 
has  a much  longer  stroke,  so  as  to  raise  the  slack  given  to  the  closing 
chain  and  so  allow  the  passage  of  ships.  Both  chains  are  fastened 
to  the  bottom  of  the  lock.  After  passing  around  the  guide  pulleys 
placed  on  the  gates  they  pass  around  the  tackles  of  the  opening 
and  closing  apparatus,  placed  side  by  side,  and  set  in  motion  by  a 
single  valve. 

The  lower  guide  pulleys  are  mounted  on  a swivel  block,  allowing 
them  to  take  the  different  directions,  followed  by  the  chain.  (Figs. 
127  and  128). 

The  quantity  of  water  used  for  opening  or  closing  is  308  liters. 


The  sluices  used  to  close  the  culverts  between  the  Eure  and  Bellt>t 
basin  are  cylindrical,  2.08  meters  in  diameter.  The  apparatus  for 
working  them  is  calculated  on  the  hypothesis  of  a change  of  level 
of  3 meters ; it  consists,  for  each  sluice,  of  a cylinder  with  a piston 
attached  directly  to  the  valve  rod. 

The  accumulator,  to  regulate  the  pressure,  has  a capacity  of  755 
liters,  and  the  load  corresponds  to  a pressure  of  52  kilograms  per 
square  centimeter. 

A steam  engine  of  15  horse  power  is  provided,  to  take  the  place  of 
the  accumulator  in  case  of  need. 

The  compressing  pumps  consist  of  three  sets  of  plunger  pumps, 
coupled  to  the  same  shaft  by  three  cranks  120  degrees  from  each 

other. 

The  amount  furnished  is  53  liters  per  minute.  This  quantity 
allows  a complete  opening  and  closing  of  the  bridge  every  twenty-five 


700 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


minutes,  which  is  sufficient  to  guarantee  the  service  in  case  of  acci- 
dent to  the  pipes. 

Cost. — The -cost  of  the  lock  is  estimated  at  1,980,000  francs.  The 
engineers  who  prepared  the  project  and  directed  the  works  are, 
MM.  Bellot  and  Quinette  de  Rochemont,  chief  engineers ; Renaud 
E.  Widmer  and  H.  Desprez,  assistant  engineers. 

IRON  DOCK  SHEDS. 

(211)  Description  of  the  sheds. — The  first  principle  laid  down  in 
the  construction  of  the  sheds  was  to  diminish,  as  much  as  possible, 
compatible  with  an  economical  construction,  the  number  of  the  sup- 
ports. 

The  pillars,  which  rise  in  the  middle  of  the  covered  surfaces,  take 
up  the  place  of  merchandise  and  are  a notable  obstacle  to  traffic. 
This  hindrance  is  especially  sensible  at  Havre,  where  the  transporta- 
tion by  carts  has  an  important  place. 

For  the  southern  sheds  (PI.  VIII)  there  are  two  spans  of  27.50  me- 
ters. The  roof  trusses  are  spaced  1G  meters  and  united  by  longitu- 
dinal lattice  girders  parallel  to  the  quay. 

The  principal  dimensions  are  given  in  the  following  table: 

Meters. 


Span  of  the  trusses 27. 50 

Distance  apart  of  the  principal  trusses 16.00 

Total  height 12. 60 

Height  of  the  side  doors 4. 75 

Construction  of  the  purlins  (lattice): 

Height  of  the  purlins 0. 60 

Distance  apart  of  the  purlins 1.75 


The  cost  of  the  sheds  varies  according  to  their  dimensions.  The 
cost  of  this  shed  was  42  francs  per  square  meter,  covered. 

Chapter  XXI. — Port  of  Havre— Iron  wave  breaker  on  the 

BREAKWATER  AT  THE  SOUTH  SIDE  OF  THE  OUTER  HARBOR. 

(212)  Three  sloping  breakwaters  are  placed  at  the  entrance  of  the 
port  of  Havre,  two  on  the  north  bank  and  one  on  the  south  bank  of 
the  channel.  To  prevent  the  ships  from  running  into  the  masonry 
of  these  works,  and  to  permit  the  passage  of  pedestrians  along  the 
channel,  a wave-breaker  has  been  constructed  on  the  sill  of  each  of 
the  breakwaters.  The  northern  wave-breakers  are  of  wood,  that  at 
the  south  is  of  iron.  It  is  100  meters  long  and  its  plan  is  curved. 
It  has  a height  of  8.50  meters,  measured  from  the  sill  of  the  break- 
water (at  the  reference  2.15  meters)  to  the  footpath  which  forms  the 
coping,  at  the  reference  of  10.  G5  meters. 

It  consists  (Fig.  129)  of  sixteen  trusses  G meters  apart ; each  truss 
consists  of  (1)  a bedplate,  e c,  united  to  a vertical  web  by  two  angle 


Paris  Exposition  op  1889 — Vol.  3.  Civil  Engineering,  etc.— PLATE  VIII. 


FRAME  WORK  OF  THE  IRON  DOCK  SHEDS  AT  HAVRE. 


CIVIL  ENGINEERING,  ETC. 


701 


irons  built  into  the  masonry;  (2)  a corner  post,  a b,  formed  of  two 
channel  irons  placed  hack  to  back  and  united  to  the  plate  by  two 
channel-iron  beams ; (3)  a diagonal  brace,  e d,  equally  of  channel 
iron,  united  at  the  extremity  to  the  plate,  next  to  a b,  and  to  the  two 
diagonal  beams  c s and  m n,  and  supporting  at  its  upper  extremity 
the  end  of  the  roadway;  (4)  a horizontal  beam,  a d,  placed  in  the 
upper  part ; (5)  two  intermediate  pieces,  t u,  and  v x,  uniting  the  cor- 
ner post  and  the  diagonal  brace  e d.  The  corner  post  has  a batter  of 
one-fifth. 

The  trusses  are  united  by  flush  iron  parapets,  and  also  by  seven 
horizontal  rails  of  channel  iron,  riveted,  behind  the  corner  post,  upon 
the  diagonal  beams  and  upon  the  two  intermediate  pieces ; besides, 
they  are  connected  on  the  interior  by  iron  tie-rods. 


Fig.  129.— Iron  wave  breaker. 


Between  two  consecutive  trusses  there  are  three  intermediate  posts 
identical  with  the  corner  posts  and  spaced  1.50  meters.  They  rest 
upon  horizontal  rails,  and  their  feet  are  imbedded  in  the  masonry 

sill. 

The  corner  posts  are  cased  witli  oak.  The  footbridge  is  formed  of 
of  four  courses  of  double  T iron  supporting  an  oak  flooring.  It  is 
furnished  with  two  wrought-iron  parapets  0.80  meter  high,  sur- 
mounted by  wooden  hand  rail.  It  is  3 meters  wide. 

The  iron  is  galvanized.  The  oak  casings  are  protected  by  large 
headed  nails  driven  in  below  just  to  the  level  of  the  water;  they  are 
tarred  above. 

The  trusses  are  put  together  in  the  breakwater  chambers,  then 
raised  and  fastened  without  any  difficulty.  The  design  was  pre- 
pared and  the  work  directed  by  MM.  Quinette  de  Rochemont  and 
Maurice  Widmer,  engineers,  under  the  orders  of  M.  Bellot,  engineer 

in  chief. 


702 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


Chapter  XXII. — Canal  from  Havre  to  Tancarvilie — Single 

GATE  OF  THE  TaNCARVILLE  LOCK. 

(213)  The  canal  from  Havre  to  Tancarvilie  was  built  to  facilitate 
commerce  between  Havre  and  the  Seine  and  to  avoid  the  dangers  of 
traversing  the  estuary  by  "canal  barges.  It  begins  at  Havre  and  en- 
ters the  Seine  near  Tancarvilie,  96  kilometers-  below  Rouen.  Its 
total  length  is  25  kilometers. 

The  canal  is  formed  of  a single  bay.  The  position  of  the  water 
level,  intermediate  between  high  tide  and  low  tide  at  Havre,  and  the 
high  tide  and  low  tide  at  Tancarvilie,  required  the  construction  of 
two  locks,  one  at  Havre  and  the  other  at  Tancarvilie.  In  order  to 
be  able  to  lock  boats  under  all  circumstances  each  one  of  these  locks 
is  furnished  with  gates  closing  in  both  directions. 

The  Tancarvilie  locks  are  furnished  with  four  single-leaf  gates 
(Figs.  130-133).  These  four  gates  have  in  plan  the  same  dimensions. 
They  only  differ  in  height.  Their  upper  part  is  0.05  meter  above 
the  maximum  high  water  which  they  have  to  sustain.  At  their 
lower  part  they  bear  0.20  meter  against  the  masonry  sills.  The  flood 
gates  are,  respectively,  9.85  and  9.25  meters  in  height.  The  ebb 
gates  are  7.85  and  7.25  meters.  Their  maximum  width  is  4.02  meters. 
Their  length  is  18.75  meters.  When  they  are  put  in  the  lock  cham- 
ber they  rest  0.20  meter  behind  the  face  of  the  wall. 

Each  of  these  gates  is  built  so  as  to  float,  whatever  may  be  the  height 
of  the  surrounding  water  above  its  minimum  level,  which  is  that  of 
low  tide  (2.75  meters).  For  this  purpose  a horizontal  beam  with  a 
flush  web  is  placed  at  this  level,  which  forms  a tight  deck  and  con- 
stitutes a compartment  of  the  lower  part  of  the  gate,  where  the  bal- 
last is  placed,  and  where  the  water  can  never  get  in.  Upon  this 
horizontal  deck  three  vertical  lattice  beams  are  placed,  upon  which 
are  put  two  horizontal  belts.  These  belts  support  vertical  members 
on  which  the  sheet-iron  skins  are  riveted. 

The  gate  is  completed  at  one  of  its  extremities  by  a rectangular 
compartment  2.25  meters  long,  and  is  furnished  with  a trunnion  at  its 
upper  part  and  a bearing  at  its  lower  part.  The  trunnion  works  in 
a collar  fixed  in  the  masonry,  and  the  bearing  rests  on  a pivot  fast- 
ened into  the  invert. 

Wooden  casings  fixed  to  the  gato  insure  the -tightness  of  the  con- 
tact of  the  leaves  and  sill. 

Iron  culverts,  capable  of  being  closed  by  sluices,  allow  the  water 
in  the  canal  to  penetrate  freely  into  the  gate  above  the  tight  deck,  so 
that  when  the  water  rises  above  the  reference  2.75  meters  the  equi- 
librium is  not  disturbed. 

Iron  shafts  rise  from  the  deck  just  to  the  upper  part  of  the  gate, 
so  that  the  lower  compartment  can  always  be  inspected  and  the  bal- 
last handled.  They  are  ordinarily  closed  by  a tight  cover. 


CIVIL  ENGINEERING,  ETC. 


703 


The  gates  were  constructed  in  the  locks  themselves,  which  wero 
pumped  out  for  the  purpose.  The  compartment,  2.25  meters  long, 
which  forms  the  heel  post,  was  carried  from  the  workshop  all  put 
together.  It  was  placed  immediately  upon  the  pivot  and  served  as 
a base  for  mounting  the  rest  of  the  leaf. 


When  a gate  has  to  be  repaired  the  sluices  of  the  culverts  are 
closed  at  low  tide.  The  tide  rises,  lifting  the  gate,  which  is  made  fast 
to  the  side  of  a barge  to  avoid  any  chance  of  accident,  and  is  then 


704 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


carried  into  the  dry  dock  at  Havre.  It  is  brought  back  and  placed 
upon  its  pivot  during  ebb  tide.  At  low  tide  the  collar  is  put  on  and 
the  culvert  sluices  are  raised. 

This  new  system  of  gate  was  invented  by  M.  Bellot  when  he 
was  chief  engineer  at  Havre.  It  presents  several  advantages  over 
the  system  in  general  use.  In  certain  cases,  especially  at  Tan 
carville,  there  is  economy  in  the  masonry.  Great  difficulties  are 
avoided  in  making  the  gate  itself,  the  dimensions  of  which  need  not 
have  great  precision  in  order  that  its  tightness  be  absolute. 

Slight  variations  in  the  form  of  the  leaves  do  not  prevent  this 
tightness. 

When  the  gates  are  exposed  to  the  waves  or  a strong  current  the 
miter  gates  are  exposed  to  shocks  which  are  liable  to  break  the  col- 
lars. The  one-leaf  gates  only  beat  upon  their  edges  and  the  chance 
of  accident  is  very  much  less. 

Finally,  the  operation  is  simplified,  and  the  closing  of  one  leaf  is 
effected  without  the  attention  which  is  required  in  miter  gates.  The 
superiority  of  the  system  is  also  shown  in  the  various  accidents  which 
would  have  broken  miter  gates  when  the  single  leaf  has  resisted  per- 
fectly. 

The  designs  for  the  Tancarville  gates  were  prepared  and  the  work 
directed  under  the  orders  of  MM.  Bellot  and  Quinette  de  Rochemont, 
chief  engineers,  by  M.  Maurice  Widmer,  assistant.  The  gates  were 
built  by  M.  Baudet,  Donon  & Co.,  constructors,  Paris. 

Chapter  XXIII. — Slipway  built  by  the  chamber  of  commerce 
at  Rouen  for  the  repair  of  ships. 

(211)  The  port  of  Rouen  has  been  completely  changed  since  1887. 
Actually  none  of  the  old  quays  are  left;  they  have  all  been  replaced 
by  new  ones.  A timber  basin  bordered  with  quays  1,185  meters 
long  with  an  area  of  125,000  square  meters  has  been  finished,  also 
a petroleum  dock  having  accessible  banks  of  1,4G0  meters  with  six 
landing  stages  and  an  area  of  115,000  square  meters. 

(215)  The  chamber  of  commerce  has  lately  built  a slipway  accord- 
ing to  Labat’s  system  which  may  be  described  as  follows  : 

The  transverse  slipway  at  Rouen  is  90  meters  long;  it  can  accom- 
modate ships  95  meters  long  and  weighing  1,800  tons.  The  slope  is 
20  per  cent ; its  width  is  51.30  meters,  and  the  travel  of  the  cradle  is 
31.51  meters,  corresponding  to  a rise  of  7.16  meters. 

It  can  be  traversed  in  5,  3£,  or  2 hours  according  to  the  coupling  of 
the  winding  gear. 

When  the  cradle  is  at  the  bottom  of  its  course,  the  level  of  the 
keel  blocks  is  4.50  below  high  water;  when  it  is  at  the  top,  this  level 
is  1 meter  above  high  water. 

The  inclined  plane  is  formed  of  forty-two  beams  (Figs.  134.  135, 
138)  resting  on  piles  united  together  by  bridle  pieces.  These  beams 
support  steel  rails. 


. 134. — Slipway  at  Rouen.  General  plan. 


Fig.  136.— Hauling  machinery. 


CIVIL  ENGINEEKING,  ETC. 


707 


The  cradle  is  formed  of  forty-two  box-girders  firmly  braced,  cor- 
responding to  the  forty-two  beams  of  the  inclined  plane  ; each  girder 
carries  also  a steel  rail.  Between  these  two  sets  of  rails,  strings  of 
rollers  are  placed  on  which  the  cradle-truck  rolls. 

The  cradle  is  divided  into  two  parts,  49. 3G  and  40.44  meters  in 
length,  which  can  be  worked  together  or  separately,  so  as  to  raise 
a large  ship  or  two  small  ones.  On  the  land  side  the  cradle  carries 
a service  bridge  high  enough  to  be  always  out  of  water. 

The  hauling  chains,  forty  in  number,  are  attached  to  movable 
sheaves  placed  midway  between  the  beams  of  the  cradle  ; these  pul- 
leys being  connected  by  a compensating  cable  (Fig.  137)  which  divides 
equally  the  tension  between  all  the  chains.  This  cable  passes  alter- 
nately around  one  of  the  movable  pulleys  and  a pulley  fixed  to  the 
cradle.  Its  ends  are  attached  to  the  cradle. 


1 

1 

; 

I 

i 

V/ 

u 

1 

m 

u 

Ij 

! 

- 

Fig.  137.— Method  of  attaching  the  compensating  cable  to  the  cradle. 


Each  traction  chain  passes  round  a winch  drum  driven  by  an  end- 
less screw,  which  is  itself  driven  by  bevel  gearing  and  a counter  shaft 
(Fig.  13G)  extending  the  whole  length  of  the  slip.  The  engine  gives 
a power  of  50  horses  measured  on  the  shaft. 

(216)  The  rollers. — The  rollers  are  independent  of  the  roadway 
and  the  cradle.  They  are  of  chilled  iron,  0.14  meter  in  diameter, 
and  0.18  meter  long.  Each  has  a ridge  in  the  middle  which  runs  in 
a groove  in  the  rails  ; they  are  united  by  iron  rods,  which  keep  them 
at  the  constant  distance  of  0.56  meter  apart.  Independent  rollers 
have  the  advantage,  over  a system  of  wheels  fixed  to  the  cradle,  of 
avoiding  the  axle  friction ; rolling  friction  only  has  to  be  overcome, 
which  is  estimated  at  3 per  cent,  besides  avoiding  inequalities  of 
pressure,  combined  with  simplification  in  construction. 

(217)  The  compensating  cable  is  of  steel  50  millimeters  in  diame- 
ter; it  distributes  the  total  force  of  traction  equally  upon  forty  tension 
chains.  The  pulleys  are  all  0.G0  meter  in  diameter,  the  movable 


708 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


ones  sliding  in  guides  0.20  meter  long.  In  case  of  tlie  rupture  of  a 
chain,  the  movable  pulley  will  be  carried  to  the  bottom  of  its  guide, 
the  compensating  cable  will  continue  to  pull  upon  it  and  will  distri- 
bute its  load  equally  among  the  other  chains. 

In  case  of  the  rupture  of  the  compensating  cable,  the  cradle  trucks 
will  descend  a few  centimeters  and  the  movable  pulleys  will  be  caught 
by  frames  arranged  above  the  guides.  The  chance  of  rupture  of  the 
cable  is  small,  as  it  is  exposed  to  a tension  of  only  3b  kilograms  per 
square  millimeter. 


(218)  Cost* — M.  Labat  constructed  this  slipway  at  Rouen  for 
740,000  francs,  which  was  divided  as  follows: 


Francs. 

Earthwork 40, 000 

Foundations  and  inclined  plane 240,000 

Cradle 180,000 

Traction  tackle  . 220. 000 

Engine  and  shed 60. 000 


Total 740,000 


Chapter  XXIV. — Port  of  Hoxfleur. 

(210)  Sluicing  basin  with  a feeding  tveir  for  filling  it. — Honfleur 
Harbor  is  exposed  by  its  situation  upon  the  south  bank  of  the  Seine 
estuary  to  silting.  To  preserve  the  channel,  a sluicing  basin  with 
an  area  of  54  hectares  has  been  constructed,  filled  directly  from  the 
sea  at  high  tide  by  means  of  a weir  with  rotating  gates.  (Fig.  139). 

The  sluicing  lock  has  four  openings,  each  5 meters  wide,  separated 
by  piers  2 meters  thick,  surmounted  by  a stone  bridge.  Without 
entering  into  the  details  of  its  construction  and  cost  it  will  be  inter- 
esting to  know  bow  it  is  closed. 

* For  drawings  and  information  I am  indebted  to  the  notice  of  this  work  pre- 
sented to  the  Paris  Congress  for  harbor  works  by  M.  G.  Cadart,  engineer  of  roads 
and  bridges. 


CIVIL  ENGINEERING,  ETC. 


709 


The  apparatus  for  closing  the  sluicing  lock  (Figs.  140  and  141) 
consists,  for  each  opening:  First.  Of  two  guard  sluices,  2.45  meters 
wide,  which  prevent  leakage  as  well  as  the  inopportune  opening  of 
the  revolving  gate  by  the  waves  striking  it  from  without;  Second. 
Of  a revolving  gate  against  which  the  head  of  water  for  the  sluicing 
presses  when  the  guard  sluices  are  raised. 


Each  sluice  carries  two  racks  which  gear  with  pinions  keyed  to  a 
horizontal  shaft  above,  which  four  men  turn  by  means  of  winches 
placed  on  the  piers  or  abutments  of  the  lock.  These  racks  raise  first 
a valve  placed  at  the  base  of  the  sluice,  which  uncovers  two  orifices 
0.20  meter  high  by  1.70  meters  wide;  these  orifices  empty  the  chamber 
between  the  sluices  and  the  revolving  gate.  The  effort  to  raise  the 
sluices  is  consequently  reduced  to  that  of  lifting  their  weights.  The 


710 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS, 


Apparatus  for  closing  the  sluicing  lock  at  Honfleur. 


Fig.  140.— Vertical  half  section. 


Fig.  141.— Horizontal  section  and  plan. 


T 


CIVIL  ENGINEERING,  ETC. 


711 


rack  carries  a stop  which,  when  the  valve  is  raised,  catches  the  sluice 
and  raises  it  to  the  top  of  the  arch  of  the  bridge.  The  preliminary 
operation  of  raising  the  two  sluices  takes  two  gangs  of  four  men  an 
hour. 

The  axle  of  rotation  of  the  revolving  gate  is  0.09  meter  from  the 
middle,  and  in  order  to  facilitate  the  closing  of  the  gate  against  the 
scouring  current,  there  is  in  the  great  panel  (Fig.  141)  a valve  turn- 
ing around  a very  eccentric  vertical  axle,  which  instantly  opens  under 
the  pressure  of  the  water  as  soon  as  the  stop  which  holds  it  is  turned. 

The  great  gate,  the  two  panels  of  which  become  unequally  loaded, 
rotates  suddenly  into  the  plane  of  the  axis  of  the  lock.  To  close  the 
great  gate,  it  is  sufficient,  after  closing  and  fastening  the  rotating 
valve,  to  incline  it  slightly  to  the  lock  axis  by  means  of  a cable  fixed 
to  it  and  passing  round  the  drum  of  one  of  the  winches.  The  differ- 
ence of  head  existing  within  and  without  the  gate  causes  a difference 
of  pressure  on  the  two  panels  and  closes  the  gate. 

(220)  Construction  of  the  gates. — Each  gate  is  made  up  of  uprights 
of  oak  0.40  meter  thick,  firmly  held  at  their  extremities  by  beams  of 
double  T iron  forming  bridle  pieces.  The  plates  of  these  beams  are 
embedded  in  the  wood,  so  as  to  avoid  any  projection.  The  uprights 
are  held  together  by  three  horizontal  bolts  extending  the  whole  width 
of  the  gate ; two  belts  of  wrought  iron  strengthen  the  whole.  The 
axle  of  the  gate  is  formed  by  a double  T beam  terminated  by  two 
pivots  and  joined  with  horizontal  bridle  pieces.  The  pivots  are  of 
steel,  0.210  meter  in  diameter. 

Cost. — The  cost  of  constructing  the  gates  and  sluices  of  the  basin, 
with  the  winches,  etc.,  amounted  to  132,109  francs. 

(221)  The  feeding  weir. — The  problem  to  solve  consisted  in  intro- 
ducing layers  of  surface  water  into  the  basin  at  will  during  high  tide. 
Preliminary  experiments  showed  that  these  layers  are  always  very 
much  clearer  than  those  at  the  bottom,  and  that  by  their  use  the 
basin  would  be  prevented  as  much  as  possible  from  silting  up.  As 
there  were  only  2j  hours  at  each  tide  which  could  be  used,  a layer  of 
water  0.60  meter  in  height  by  100  meters  in  length  suffices  to  fill  the 
basin.  This  length  was  divided  into  ten  openings,  10  meters  wide, 
closed  by  three  movable  gates  (Fig.  142).  These  gates,  turning  around 
a horizontal  axis,  are  each  held  by  a chain  fixed  to  their  upper  parts. 
All  these  chains  pass  around  guide  pulleys,  and  their  extremities  are 
fixed  to  the  same  frame  mounted  on  rollers,  so  that  the  reciprocating 
motions  of  the  frame  give  simultaneous  movements  of  rotation  to 
all  the  gates.  Hydraulic  presses  move  the  frames,  either  to  raise  or 
to  lower  the  gates.  A weir  with  a movable  crest  is  thus  obtained, 
which  allows  the  introduction  into  the  basin  of  a layer  of  water  of 
constant  thickness,  notwithstanding  the  variations  of  the  sea  level, 
which  do  not  exceed  0.40  or  0.50  meter  during  the  time  of  filling. 


712 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


Description  of  Fig.  142. — A,  movable  gates,  turning  around  a horizontal  axle 
placed  at  the  lower  part  near  the  flooring ; each  gate  consists  of  eight  vertical  beams 
of  plate  and  angle  irons  connected  above  and  below  by  two  similar  crossbeams  : it  is 
covered  on  the  upstream  side  with  a plate  iron  skin,  8 millimeters  thick,  terminating 
below  in  the  form  of  a semicylinder,  so  as  to  always  remain  in  contact  with  the 
wood  casing  built  into  the  flooring  sill.  On  the  downstream  side,  at  a height  of 
1.70  meters,  is  a horizontal  beam  made  of  plate  and  angle  irons  fixed  to  the  vertical 
beams ; to  this  crossbeam  the  traction  chains  are  attached.  The  end  verticals  of 
the  gate  are  cased  with  wood.  The  gate  is  represented  in  the  figure  in  its  vertical 
position;  that  is,  when  the  weir  is  closed;  and  also  a gate  in  a horizontal  position, 
although  in  reality  it  never  takes  it.  The  figure  shows  the  inclination  of  the  gate 
during  the  process  of  filling  the  basin  when  the  level  of  the  sea  is  11.82  meters. 
a.  Forked  bearings  and  journals,  two  for  each  gate.  The  form  of  these  bearings 
allows  the  gates  to  be  removed  for  repairs  without  having  to  take  them  apart  under 
water,  c.  Plate  iron  apron,  45  centimeters  wide,  hinged  to  the  base  of  the  gate  and 
furnished  with  a leather  band  which  covers  the  joint  of  the  gates  with  the  sill.  This 
apron  drags  upon  the  flooring,  following  the  motions  of  the  gate,  and  prevents  ob- 
structions which  might  produce  accidents  at  the  moment  of  lifting,  d.  Two  ten- 
nons  for  each  gate,  fixed  to  the  upper  beam,  just  over  the  rotation  journals.  These 
tennons  are  forged  in  a single  piece,  with  a plate  which  serves  to  bolt  them  upon 
the  web  of  the  beam  ; it  is  by  means  of  these  tennons  that  the  bolts  hold  the  gates 
fast  against  the  frame  so  that  they  may  be  able  to  sustain  the  pressure  of  the  rising 
tide  while  the  storage  basin  is  empty. 

B.  Framework  holding  the  moving  mechanism  for  rotating  the  gates.  It  is 
forme  I of  two  vertical  lattice  beams  1.25  meters  high  ; these  beams,  spaced  60 
centimeters  apart,  are  jointed  below  to  a horizontal  beam,  1.20  meters  wide,  having 
a flush  web  pierced  with  holes  for  the  passage  of  the  chains.  These  three  beams  are 
braced  by  cross  partitions  of  iron,  8 millimeters  thick,  numbering  six  per  span.  A 
third  vertical  beam,  60  centimeters  high,  sustains  the  crossbeams  of  the  footbridge. 
These  latter  are  united  by  four  courses  of  crossbeams  supporting  the  planks  of  the 
service  bridge  and  the  rails  for  a moving  crane.  On  the  reservoir  side  is  a sidewalk 
on  corbels,  projecting  70  centimeters,  and  held  by  plate  iron  brackets  and  angle  irons. 

D.  Guide  pulleys  of  the  chains;  they  are  cast-iron  grooved  chain  pulleys,  their 
grooves  lined  with  bronze.  They  revolve  on  iron  shafts,  60  millimeters  in  diameter, 
having  supports  cast  in  a single  piece  and  bolted  under  the  web  of  the  horizontal 
beam. 

E.  Guide  pulleys  of  the  chains,  of  the  same  model  as  the  preceding  but  keyed  to 
the  shaft.  The  plumber  blocks,  inclined  at  45°,  are  fixed  at  60  centimeters  apart 
upon  the  upper  plates  of  the  vertical  beams ; the  shaft  of  these  pulleys  is  65 
millimeters  in  diameter  at  the  bearings  and  90  millimeters  in  the  middle.  The 
plumber  blocks  are  furnished  with  a half  lining  in  bronze,  and  an  iron  cap. 

F.  Reciprocating  frames  for  rotating  the  gates  simultaneously.  Each  frame  is 
formed  of  two  plate-iron  beams  300  millimeters  high,  75  thick  and  250  apart,  united 
by  transverse  ties  G ; a gate  chain  is  attached  to  each. 

G.  Cross  girders,  having  their  ends  bolted  upon  the  sides  of  the  moving  frame  so 
that  they  can  be  removed.  The  chains  are  fixed  upon  these  cross  girders  by  means 
of  turn-buckles  which  allow  their  length  to  be  regulated,  so  that  at  the  closing  all 
the  gates  shall  come  against  the  framework.  The  frame,  by  its  reciprocating  mo- 
tion, determines  the  simultaneous  rotation  of  the  gates. 

The  chains  are  round,  30  millimeters  in  diameter.  They  contain,  each  one,  59 
links,  85  by  38  millimeters  of  opening,  and  two  end  links  124  by  38  millimeters. 

R.  Iron  rollers,  twenty  for  each  frame.  These  rollers  are  18  centimeters  in  diam- 
eter, 42  long.  Their  iron  axles,  4 centimeters  in  diameter,  turn  in  boxes  fixed  on 
the  vertical  beams  of  the  frame. 

b.  Chair  supporting  the  bolts. 

t.  Bolt  shaft. 


'■  142.— Partial  elevation  and  cross  section  of  the  feeding  weir  gates  of  the  sluicing  basin. 


CIVIL  ENGINEERING,  ETC. 


713 


Sluicing  basin  at  the  pout  of  Honfleur. 


714 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


(222)  The  feeding  weir  consists  of: 

First.  Ten  openings,  formed  by  nine  piers  and  two  abutments. 
These  openings  are  each  10  meters  wide  and  11.75  meters  long. 
Their  invert  in  the  highest  part  is  at  the  reference  14  meters,*  so  as 
to  allow  the  filling  of  the  basin  in  the  lowest  tides,  the  highest  attain- 
ing the  reference  of  13  meters.  The  flood  gates  occupy  a space  of 
10.20  meters  wide  and  6.45  long,  corresponding  to  each  opening.  A 
building  on  the  central  pier  contains  the  hydraulic  machinery  and 
the  lodging  of  the  machinist. 

Second.  Thirty  iron  flood  gates,  three  for  eacli  opening,  turning 
on  horizontal  bearings  embedded  in  the  invert  of  the  opening. 
These  flood  gates  rise  from  the  invert  (reference  14  meters)  to  the 
level  of  the  equinoctial  high  tide,  which  reaches  the  reference  11.82 
meters. 

Third.  An  iron  frame  work  built  on  piles  and  supporting  the  upper 
edge  of  the  flood  gates ; it  carries  the  guide  pulleys  of  the  lifting 
chains  and  the  rollers  upon  which  the  frames  move,  and  forms  at 
the  same  time  a bridge  of  communication  on  which  a tliree-ton 
crane  runs,  which  allows  any  piece  to  be  taken  out  and  replaced 
very  rapidly. 

Fourth.  The.  transmitting  mechanism,  consisting  of  chains  and  a 
movable  frame.  This  last  is  jointed  to  a rod  driven  by  two  twin 
presses  moved  by  water  under  the  pressure  of  70  kilograms  per 
square  centimeter.  The  other  extremity  of  the  frame  is  drawn  by 
a counterpoise  intended  to  overcome  the  passive  resistances  of  the 
apparatus  during  the  opening  of  the  flood  gates. 

Fifth.  The  mechanism  for  keying,  intended  to  maintain  the  flood 
gates  against  the  frame  work,  to  permit  them  to  resist  the  pressure 
of  the  rising  tide  just  to  the  moment  of  filling.  This  mechanism 
consists  of  a shaft  carrying  a series  of  pins,  two  for  each  flood  gate, 
driven  by  a little  special  hydraulic  press. 

(223)  The  movement  of  the  gates  is  effected  by  means  of  two  cou- 
pled hydraulic  presses.  A little  double-cylindered  steam  engine  of 
9 horse-power  works  the  pumps  for  filling  the  accumulator,  or,  if 
necessary,  drives  the  water  directly  into  the  cylinders  of  the  great 
presses. 

The  accumulator  contains  600  liters  of  water  at  a pressure  of  70 
kilograms  per  square  centimeter. 

The  water  discharged  by  the  hydraulic  apparatus  during  the  low- 
ering of  the  gates  is  collected  in  an  iron  tank  placed  on  brackets  let 
into  the  wall  of  the  engine  room.  From  this  reservoir  the  pumps 
take  the  water  required  for  their  use.  This  is  an  important  economy, 
since  the  apparatus  has  to  be  fed  with  fresh  water  brought  from  the 
city. __ 

*The  datum  plane  for  Honfleur  is  16.087  meters  above  that  adopted  for  the  rest 
of  France. 


CIVIL  ENGINEERING,  ETC. 


715 


The  complete  operation  of  the  weir  consists : first,  at  the  moment 
of  high  tide,  the  basin  being  empty,  in  gradually  lowering  the  gates, 
so  that  their  crests  shall  be  covered  by  a sheet  of  water  0.00  meter 
thick;  second,  in  raising  the  gates  when  the  basin  is  full,  that  is  to 
say,  generally,  with  a difference  of  level  if  not  nothing  at  least  in- 
significant. 

(254)  Cost. — The  expense  of  constructing  the  feeding  weir  amounted 
to  $1,224,888.30  francs. 

The  sluicing  operations  are  entirely  successful,  and  it  is  only  suffi- 
cient to  make  one  or  two  at  each  tide  to  keep  the  outer  channel  clear. 

The  feeding  weir  -works  regularly,  but,  at  the  same  time,  the  in- 
tense current  produced  on  the  approaches  to  the  weir,  when  the  re- 
volving gates  are  lowered,  does  not  exclude  absolutely  the  lower 
turbid  layers  of  water. 

The  preliminary  plan  was  made  by  M.  Arnoux,  and  the  work  was 
directed  by  MM.  Leblanc  and  Widmer,  engineers. 

The  contractors  were  M.  Hersent  for  the  lock,  and  the  Fives  Lille 
Co.  for  the  iron  work  of  the  weir. 

Figs.  139-141  are  taken  by  permission  from  the  Portefeuille  des 
Pouts  et  Chaussfies. 

Chapter  XXV. — Port  of  Honfleur — Siphons  between  the 

STORAGE  BASIN  AND  THE  FOURTH  LOCK — AUTOMATIC  SIPHONAGE. 

(225)  As  lias  been  stated,  Honfleur  Harbor  is  exposed,  by  its  situa- 
tion upon  the  south  bank  of  the  Seine  estuary,  to  Considerable  silting 
up,  against  which  constant  efforts  have  to  be  made.  The  storage 
basin  of  54  hectares  affords  the  principal  means  of  keeping  the 
passes  free  by  sluicing. 

When  great  sluicings  are  not  made,  communication  is  opened  be- 
tween the  docks  and  the  storage  basin,  in  order  to  increase  the  effi- 
ciency of  the  sluicing  given  by  the  navigation  locks,  and  to  reduce 
the  silting  of  the  docks  by  raising  as  much  as  possible  the  level  of 
the  water  of  these  last,  before  the  opening  of  the  ebb  gates  and  in- 
troduction of  the  flood,  which  is  very  much  loaded  with  sand.  This 
communication  ought  not  to  be  opened  more  than  five  or  six  times  a 
fortnight,  to  reestablish  the  level  in  the  dock  when  this  level  has 
fallen  below  that  of  the  storage  basins  on  account  of  the  sluicing. 
The  level  of  the  storage  basin  being  generally  above  that  of  the  dock, 
there  was  great  interest  in  making  a tight  closing.  This  motive, 
joined  to  that  of  economy,  led  to  the  adoption  of  a system  of  siphons. 
These  siphons  are  six  in  number.  The  saddle  is  placed  above  the 
ordinary  level  of  the  basins  (12.30  meters). 

(226)  The  apparatus  for  filling  and  emptying  is  based  upon  the  fol- 
lowing experiments.  When  a small  hole  is  made  in  the  wall  of  a 
siphon  in  operation,  in  the  portion  where  the  pressure  is  below  that 
of  the  atmosphere,  the  siphon  does  not  become  clear  if  the  hole  is 


716  UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 

very  small.  The  external  air  is  sucked  by  this  orifice  into  the  siphon, 
and  it  issues  in  great  bubbles  which  break  upon  the  surface.  By 
enlarging  the  orifice,  or  by  piercing  other  holes  near  the  first,  we 
finally  clear,  i.  e.,  empty  the  siphon. 

In  opening  the  sucking  orifice  to  bring  about  the  clearing,  we  ob- 
serve that  the  flow  of  the  latter  diminishes  progressively  until  it  at- 
tains a value  very  near  zero,  and,  for  an  opening  slightly  more,  the 
clearing  is  nearly  instantaneous.  It  is  evident  that  this  principle 
may  be  applied  to  the  filling  of  siphons  of  great  capacity. 

Small  siphons  are  filled  easily  and  rapidly,  either  by  the  emptying 
of  a reservoir  full  of  water,  or  by  means  of  a sucking-pump.  A lit- 
tle siphon  pierced  with  a sucking  orifice  properly  arranged  will  work 
as  a filler  for  siphons  of  greater  dimensions,  if  we  unite  the  pierced 
sucker  of  the  first  to  the  top  of  the  second.  To  stop  the  action  it 


will  suffice  to  clear  the  siphons  by  putting  them  in  communication 
with  the  atmosphere  by  an  orifice  sufficiently  large. 

(227)  This  stated,  the  process  of  filling  can  be  understood ; it  is  as 
follows:  A valve  a (Fig.  143)  is  opened  which  allows  the  water  in 
the  reservoir  A to  flow  into  the  pit  P,  and  thence,  through  the  con- 
duit B,  into  the  lower  bay;  at  the  same  time  the  upper  part  of  the 
leservoir  A is  connected  with  the  top  of  the  filling  siphon,  No.  1. 
The  capacity  of  the  reservoir  A is  calculated  so  that  all  the  air  con- 
tained in  the  siphon  is  sucked  in  and  replaces  the  water  which  runs 
out  by  the  valve  a.  When  the  siphon  is  filled,  which  is  indicated 
by  a gauge,  the  stopcocks  and  the  valve  a are  closed.  The  siphon 
No.  1 contains  an  air  sucker  formed  by  a copper  pipe  0.02  meter  in  di- 
ameter, which  goes  through  the  siphon  wall  perpendicularly,  and, 


CIVIL  ENGINEERING,  ETC. 


717 


returning  along  the  axis  of  the  siphon,  terminates  a litte  beyond 
the  top  by  a rose.  The  object  of  this  arrangement  is  to  divide  the 
air  at  its  entrance  into  the  siphon  and  to  obtain  the  rapid  drawing 
of  air  bubbles  toward  the  discharge.  The  aggregate  of  all  the  ori- 
fices of  the  rose  is  above  one-tenth  of  the  section  of  the  pipe  of  0.02 
meter.  When  the  difference  of  level  is  equal  to  or  above  0.80  meter, 
experience  shows  that  this  sucker  may  be  put  in  free  communication 
with  the  atmosphere  without  clearing  siphon  No.  1.  For  siphons 
of  the  same  cross-section  the  size  of  the  sucker  orifice  depends  on 
the  difference  of  level,  and  the  sucker  belonging  to  siphon  No.  1 is 
contrived  for  a difference  of  about  1 meter. 

The  sucker  just  described  is  put  in  communication  with  a siphon 
No.  2,  which  has  the  same  diameter  as  No.  1,  but  is  placed  0.25  meter 
higher.  The  air  contained  in  No.  2 is  drawn  out  by  this  siphon  and 
the  siphon  fills,  as  the  corresponding  manometer  indicates.  This 
siphon  contains  a sucker  identical  with  the  first,  but  with  a slightly 
less  section  (0.015  meter  instead  of  0.02  meter).  The  two  sucking 
siphons  are  putin  communication  with  a third  siphon,  called  a cul- 
vert siphon ; when  the  manometer  indicates  that  the  first  culvert 
siphon  is  filled,  a second  culvert  siphon,  connected  with  the  first,  is 
filled,  by  taking  care  not  to  uncover  a new  distributing  orifice  until 
after  the  complete  filling  of  the  preceding  siphon.  One  man  fills  all 
the  siphons.  This  operation  requires  from  ten  to  twelve  minutes. 
The  siphons  filled,  the  reservoir  A is  filled  by  putting  it  in  com- 
munication on  one  side  with  the  siphons  and  on  the  other  with  the 
upper  basin.  All  the  air  contained  in  this  reservoir  is  sucked  out 
by  the  siphons  and  replaced  by  water  from  the  upper  basin.  The 
communication  should  be  closed  when  the  water  in  both  basins  is 
sensibly  at  the  same  level.  To  stop  the  action  of  the  siphons  they 
are  cleared  by  opening  the  stopcock  of  0.02  meter,  which  puts  them 
into  communication  with  the  atmosphere.  The  complete  clearing 
takes  place  in  seven  or  eight  minutes. 

(228)  Automatic  filling. — Independently  of  the  process  of  filling 
that  has  just  been  described,  and  which  has  worked  since  1884,  these 
siphons  fill  naturally  and  automatically  whenever  the  sluicing  basin 
is  filled.  The  water  then  covers  the  saddle  of  a siphon  0.0G  meter 
in  diameter,  which  goes  down  into  the  well  and  fills  by  overflow. 
This  siphon  fills  a second  of  0.13  meter  in  diameter  placed  0.33 
meter  above  it;  and  these  two  siphons  united  fill  three  others  of  0.20 
meter  in  diameter  placed  at  0.28  meter  above  the  second.  This  col- 
lection of  fillers  is  united  with  siphon  No.  1,  which  is  0.50  meter  in 
diameter,  by  a stopcock.  When  this  cock  is  open  all  the  siphons  fill 
in  one  hour  and  a half  or  two  hours,  for  a difference  of  level  which 
ought  to  be  above  0.40  meter.  This  is  the  necessary  time  for  the  de- 
cantation of  the  water  taken  at  the  moment  of  high  tide  in  the  sluic- 
ing basin.  This  collection  of  filling  siphons,  arranged  in  a series, 
has  worked  regularly  without  aid  of  any  person  since  the  year  1886. 


718 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


The  collection  previously  described  only  works  occasionally. 

The  siphons  were  planned  and  built  by  M.  Picard,  under  the  di- 
rection of  M.  Boreux,  chief  engineer. 

Chapter  XXVI. — Traversing  bridge  over  the  dock  locks  at 
the  port  of  St.  Malo-St.  Servan. 

(229)  Position  and  general  arrangement.— The  new  road  uniting 
the  cities  of  St.  Malo  and  St.  Servan  passes  over  the  two  locks  18 
meters  wide,  of  the  two  docks,  by  means  of  traversing  bridges  moved 
by  water  under  pressure. 

These  bridges  are  similar,  each  one  having  a total  length  of  38.80 
meters— 22.80  meters  for  the  span  and  1G  meters  for  the  breech. 
The  total  width  is  8 meters,  the  width  of  the  wagon  road  5 meters, 
and  that  of  the  sidewalk  1 meter. 


Fig.  144. — Section  of  the  traversing  bridge — Section  A B of  the  box  girder- -Sections  C D and  E F of 

the  lifting  press. 

Idie  roadway  is  carried  by  two  principal  girders  with  flush  webs, 
having  the  form  approaching  that  of  a solid  of  equal  l’esistance;  the 
maximum  height  being  2.814  meters.  The  upper  flange  is  curved, 
the  lower  straight.  The  cross  girders  are  spaced  2 meters. 

(230)  The  lifting  press  (Fig.  144),  1.06  meters  in  interior  diameter, 
is  placed  vertically  in  a masonry  pit  exactly  under  the  centre  of 
gravity  of  the  bridge,  and  supports  an  iron  box  girder  on  whose  ex- 
tremities cast-iron  sleepers  are  placed  directly  under  the  principal 
girders,  and  designed  to  support  the  whole  weight;  laterally  itis 
fitted  to  pieces  of  iron  which  move  in  vertical  guides. 


CIVIL  ENGINEERING,  ETC 


719 


In  order  to  diminish  the  quantity  of  water  at  the  pressure  of  GO 
atmospheres  Mr.  Barret,  engineer  of  the  docks  at  Marseilles,  invented 
a special  apparatus,  called  a recuperator,  which  forms,  with  the  lift- 


Fig.  145. — Diagram  of  the  operation  of  the  recuperator. 


ing  press,  a sort  of  hydrostatic  balance,  allowing  the  work  produced 
by  the  descent  of  the  bridge  to  be  stored  up  and  utilized  for  raising 
it  afterwards. 


720 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


(231)  The  recuperator. — The  working  of  the  species  of  hydrostatic 
balance  of  the  recuperator  press  may  be  represented  by  the  diagram 
(Fig.  145). 

The  press  A communicates  directly,  by  the  pipe  T.  with  the  recu- 
perator  B.  The  latter  consists  of  a vertical  cylinder,  in  which  a 
piston  supporting  a loaded  box,  C,  moves.  The  load  is  regulated  so 
that  the  bridge,  P,  in  descending  drives  the  water  of  the  press  under 
the  piston  of  the  recuperator  and  raises  the  whole  system.  A pipe, 
o,  allows  water  under  pressure  to  be  introduced  at  will  into  the  an- 
nular space  over  the  piston  of  the  recuperator,  between  the  piston 
rod  and  the  cylinder,  or  to  allow  this  water  to  escape.  In  the  case 
of  the  introduction  of  this  water  the  pressure  exercised  in  the  an- 
nular space  is  added  to  the  weight  of  the  load.  The  piston  of  the 
recuperator  descends  and  drives  the  water  into  the  lifting  press.  In 
case  of  the  escape  of  the  water  the  pressure  in  the  annular  space  is 
relieved;  the  Aveiglit  of  the  bridge  again  becomes  greater  and  raises 
in  its  turn  the  piston  and  its  load. 

The  preceding  theoretical  arrangement  was  modified  in  practice 
so  as  to  avoid  having  to  take  away  the  load  of  the  piston  each  time 
that  it  was  necessary  to  change  the  packing.  The  apparatus  is  re- 
versed,  the  piston  and  piston  rod  are  fixed,  while  the  cylinder  is  mov- 
able and  carries  the  load;  so  that  to  change  the  packing  it  is  only 
necessary  to  raise  the  cover  of  the  cylinder.  Fig.  146  shows  the 
arrangement  adopted. 

The  piston  rod,  A,  is  a hollow  cast-iron  cylinder  48  centimeters  in 
diameter,  which  rests  upon  a circular  foot  1.40  me- 
ters in  diameter,  strengthened  by  flanges.  The  rod 
is  furnished  above  with  iron  rings,  forming  a piston 
of  54  centimeters  in  diameter,  packed  Avitli  tAvo 
leather  collars  all  kept  in  place  by  a cast-iron  fol- 
lower bolted  down.  (Fig.  147). 

The  interior  of  the  rod  (Fig.  146)  forms  a com- 
munication, through  the  pipe,  a,  between  the  lifting 
press  and  the  movable  cylinder  of  the  recuperator. 
This  last  is  54  centimeters  in  interior  diameter  and  80  millimeters 
thick.  It  has  an  enlargement  beloAV  and  a stuffing  box  for  the  pas- 
sage of  the  rod.  To  bring  the  Avater  from  the  accumulators  into  the 
annular  space,  C,  left  betAveen  the  rod  and  the  cylinder,  the  cylin- 
drical passageway,  B,  in  the  piston  rod  itself,  forms  the  prolongation 
of  the  pipe,  b,  and  leads  into  the  annular  space  through  a hole  pierced 
laterally  beloAV  the  piston. 

The  base  of  the  cylinder  carries  externally  tAAro  flanges  which  form 
a circular  grooA’e  for  holding  in  place  the  iron  plate  Avhich  serves  as 
the  bottom  of  the  loaded  box.  This  plate  is  made  of  two  pieces 
put  together  Avith  bolts.  The  box  is  cylindrical,  of  plate-iron  8 
millimeters  thick,  2.352  meters  in  diameter,  and  3.25  meters  high.  It 


Fig.  147.— Horizontal 
section  of  the  recu- 
perator press. 


CIVIL  ENGINEERING,  ETC. 


721 


is  guided  above  by  a cast-iron  support  having  two  arms  with  shoes, 
E E.  at  their  extremities,  which  run  on  two  cast-iron  guides,  3.45 
meters  long,  built  into  the  masonry.  Three  oak  frames  placed  above 
each  other,  at  the  foot  of  the  rod.  form  a support  1 meter  high  upon 
which  the  loaded  box  rests  when  it  is  at  the  bottom  of  its  course. 

(■-232)  The  withdrawal  and  replacement  of  the  bridge  requires,  be- 
sides the  working  of  the  hydrostatic  balance  formed  by  the  central 
press  and  the  recuperator,  some  accessory  operations.  We  must  be 
able,  in  case  of  necessity,  to  lift  the  loaded  box  to  the  top  of  its 
course,  and  on  the  other  hand  lower  or  lift  separately  the  box  girder, 
and  in  case  of  repairs,  the  plunger  of  the  central  press.  These 
operations  are  accomplished  by  the  accumulators  and  the  distributing 
apparatus  placed  in  the  pavilion  and  arranged  for  this  purpose. 

The  weight  of  the  recuperator  is  less  than  that  of  the  bridge. 

When  the  bridge  is  to  be  raised,  the  box  being  at  the  top  of  its 
course,  it  is  sufficient  to  open  the  valve,  which  puts  the  annular 
space  compirsed  between  the  piston  and  its  cylinder  in  communication 
with  the  water  under  pressure,  so  that  the  latter,  acting  on  the  lower 
face  of  the  box,  compensates  for  the  difference  between  the  weight 
of  the  bridge  and  that  of  the  box,  and  produces  the  upward  motion 
of  the  bridge. 

To  lower  the  bridge  it  is  sufficient  to  allow  the  water  to  escape  from 
the  annular  space;  the  bridge  descends  then  by  its  own  weight  and 
lifts  the -recuperator.  The  horizontal  motion  of  the  bridge  is  ob- 
tained by  two  hydraulic  presses  fixed  horizontally  on  the  vertical 
walls  of  the  box  girder  (Fig.  144)  and  moving  with  it.  They  carry  at 
each  extremity  a tackle  block  with  three  pulleys,  around  which  the 
traction  chain  passes.  One  serves  for  the  advance  motion  and  the 
other  for  the  return.  The  conducting  water  pipes  form  a joint  with 
the  cylinder  presses.  The  bridge  can  move  upon  two  pairs  of  rollers 
fixed  just  behind  the  position  it  normally  occupies — that  is,  when  the 
pass  is  closed— and  upon  four  pairs  of  movable  rollers,  which  are 
made  to  slide  upon  a cast-iron  frame  by  the  action  of  a hydraulic 
press,  which  pushes  them  under  the  bridge  as  soon  as  it  is  raised.  The 
rollers  are  fixed  in  pairs  upon  a balanced  beam,  so  that  the  weight 
of  the  bridge  shall  be  divided  equally  over  the  numerous  points  of 
support.  The  rectilinear  movements  of  the  bridge  are  limited  at 
each  extremity  by  buffers  built  into  the  masonry. 

The  complete  withdrawal  and  replacement  is  made  in  three  or  four 
minutes.  One  man  is  sufficient.  He  is  placed  in  the  pavilion  which 
contains  the  operating  keys,  the  recuperator,  and  a service  hand 
pump,  intended  to  force  in,  if  necessary,  water  enough  to  move  the 
bridge.  The  water  under  pressure  is  brought  through  one  pipe  and 
returns  in  another  to  the  pavilion  constructed  between  the  two  roll- 
ing bridges  and  containing  the  pumps  and  accumulators. 

(233)  Opening  and  closing  the  bridge. — The  pavilion  contains  three 
H.  Ex.  410— VOL  ill 46 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


7'22 

pieces  of  distributing  apparatus.  When  it  is  required  to  open  the 
pass  the  lockman  moves  the  valve  of  the  first  apparatus,  and  the 
water  under  pressure  from  the  central  machine  and  the  recuperator 
is  forced  under  the  piston  of  the  central  press,  which  raises  the 
sleeper  and  consequently  the  bridge.  Then  he  opens  the  valve  of 
the  second  apparatus  and  the  movable  rollers  slip  under  the  bridge; 
lie  then  lowers  the  bridge  upon  the  rollers  by  opening  and  discharging 
from  the  lifting  press.  When  the  bridge  rests  upon  the  rollers  he 
prolongs  a little  the  discharge  of  the  water  so  that  there  is  a play  of 
0.03  meter  between  the  sleeper  and  the  plates  of  the  beams.  Finally 
he  opens  the  valve  of  the  third  apparatus  and  the  rectilinear  mot  ion 
is  produced.  When  it  is  required  to  put  the  bridge  in  place,  the  lock- 
man  opens  the  valve  of  the  third  apparatus  and  the  bridge  is  brought 
vertically  over  its  first  position  ; then  he  opens  the  valve  of  the  first 
apparatus,  which  lets  the  water  under  pressure  into  the  central 
press.  When  the  bridge  is  sufficiently  raised  the  valve  of  the  second 
apparatus  allows  the  movable  rollers  to  be  brought  back;  then,  on 
opening  the  valve  of  the  first  apparatus,  the  bridge  sinks  to  its 
normal  position,  and  at  the  same  time  the  water  in  the  central  press 
runs  into  the  recuperator  and  is  stored  there.  The  total  weight  of 
the  bridge  is  181,500  kilograms;  the  price,  including  the  mechanism, 
the  recuperator,  and  the  piping,  amounts  to  200,000  francs.  This 
bridge  was  planned  and  made  by  M.  Robert,  engineer  of  roads  and 
bridges,  under  the  direction  of  M.  Mengin,  chief  engineer. 

Figs.  145-117  are  taken  by  permission  from  the  Portefeuille  des 
Pouts  et  Cliaussdes. 

Chapter  XXVII. — Hydraulic  works  and  pneumatic  founda- 
tions made  at  Genoa. 

(234)  Graving  docks  and  accessory  tvorks. — The  Duke  of  Galliera 
bequeathed  to  the  Kingdom  of  Italy  several  million  francs  for  the 
improvement  and  extension  of  the  harbor  of  Genoa.  Among  these 
improvements  were  particularly  specified  the  construction  of  two 
graving  docks,  capable  not  only  of  answering  the  present  require- 
ments but  also  those  which  might  arise  in  future.  A special  com- 
mission of  engineers  was  appointed  to  find  the  best  means  of  fulfill- 
ing these  obligations.  The  commission,  considering  the  exceptional 
technical  difficulties  which  this  work  presented,  advised  the  opening 
of  an  international  competition  requesting  proposals  for  the  work, 
with  the  processes  for  its  execution,  and  requiring  guaranties  there- 
for. The  administration  adopted  this  advice. 

Eight  competitors  responded  to  this  invitation  of  the  technical 
commission,  and  after  a long  examination  they  reported  in  favor  of 
the  project  presented  by  MM.  C.  Zschokke  and  P.  Terrier. 

The  works  to  be  constructed  include  principally  the  Quai  des 


CIVIL  ENGINEERING,  ETC.  723 

Graces,  the  western  quay,  the  two  docks,  the  quay  which  unites 
them,  the  pumping  machines,  and  the  caisson  gates. 

(235)  The  Quai  des  Graces  is  200  meters  long  and  75  wide.  Its 
coping  is  3 meters  above  the  level  of  the  water.  The  retaining  wall 
is  formed  of  masonry  piers  founded  by  compressed  air  upon  rock  at 
the  reference  — 8 and  united  by  brick  arches.  In  the  space  of  12 
meters  between  the  piers  the  filling  of  the  quay  is  protected  by  stone 
pitching. 

(236)  Western  quay. — The  foundations  of  this  quay  having  been 
previously  made  the  wall  alone  had  to  be  constructed. 

(237)  Graving  docks. — The  two  docks  are  parallel.  The  distance 
apart  of  their  axes  is  77.37  meters.  Their  principal  dimensions  are 
as  follows  : 


Maximum  interior  length  at  the  quay  level  including  the  entrance  chamber. 

Width  at  the  same  level 

Width  of  entrance  at  the  same  level  

Width  at  the  water  level 

Width  at  the  sill 

Height  of  the  water  on  sill  at  mean  tide 

Height  of  water  on  the  lowest  point  of  the  dock 


No.  1. 

No.  2. 

Meters. 

Meters. 

1 ~9. 38 

219.94 

29.40 

24.90 

25.28 

18.48 

24.80 

18.00 

21.06 

14.64 

9.50 

8.50 

10.00 

9.00 

The  two  docks,  although  of  different  dimensions,  are  constructed 
in  the  same  manner.  Each  entrance  has  two  recesses  for  the  caisson 

gate. 

Dock  No.  2 is  provided  with  two  other  recesses  which  are  respec- 
tively 90  and  130  meters  from  the  entrance,  and  which  allow  a second 
gate  to  be  placed  therein,  thus  dividing  the  dock  into  two  separate 
chambers,  90  and  110  meters,  or  130  and  70  meters. 

The  transverse  section  of  the  gate  chambers  is  a trapezoid.  The 
interior  lias  five  altars  in  dock  No.  1,  and  four  in  No.  2. 

The  wells  for  pumping  out  the  dock  are  in  the  walls  toward  the  en- 
trance. The  eastern  wall  of  dock  No.  2 contains  a special  culvert 
for  discharging  the  water  of  the  two  compartments  independently, 
which,  the  second  caisson  gate  allows  to  be  placed  at  the  bottom  of 
the  dock.  The  walls  approach  and  close  in  the  shape  of  an  ogive  at 
the  end  opposite  the  entrance. 

From  one  part  to  the  other  of  the  ogive  inclined  planes,  parallel  to 
the  axis  of  the  docks,  allow  the  descent  of  wagons  to  the  bottom  in 
order  to  transport  the  material  required  for  repairing  ships.  These 
inclined  planes  are  flanked  with  staircases  for  the  descent  of  the 
workmen.  The  invert  of  the  docks  has  a longitudinal  declivity  of 
1 to  100.  It  has  the  same  transverse  slope  from  the  axis  toward  the 
walls,  along  which  little  gutters  take  the  drainage  to  the  discharg- 
ing well. 


724 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


The  revetment  for  all  the  parts  of  the  work  which  are  exposed  to 
shocks  or  subject  to  strains  is  of  hewn  stone.  The  other  parts  of 
the  revetment  are  of  brick.  The  flooring  is  of  sandstone  on  brick 
foundations. 

(238)  Head  walls. — The  head  walls  are  united  with  the  Quai  des 
Graces  and  the  western  quay  by  continuous  walls,  founded  at  the 
reference  —8. 

Pumps. — The  pumping  house  is  placed  between  the  two  basins  at 
the  entrance.  Three  centrifugal  pumps,  driven  by  as  many  com- 
pound condensing  engines,  are  placed  in  a dry  pit  at  the  reference 
—8.  Two  of  these  pumps  can  clear  either  basin  filled  with  water, 
in  five  hours,  which  corresponds  to  a discharge  of  4,000  cubic  meters 
of  water  per  pump  per  hour.  Two  other  pumps,  driven  by  special 
motors,  provide  for  the  leakage ; each  one  can  discharge  250  cubic 
meters  per  hour.  The  steam  is  furnished  for  these  machines  by  six 
boilers. 

(230)  The  three  caisson  gates  are  of  plate  steel.  They  are  sur- 
mounted by  a bridge  large  enough  to  give  passage  to  wagonettes  or 
cars.  They  are  furnished  with  a number  of  sluices  sufficient  to  as- 
sure the  filling  of  one  of  the  basins  in  an  hour  at  the  most. 

EXECUTION  OF  THE  WORKS. 

(240)  Character  of  the  foundation. — The  soil  upon  which  the  works 
had  to  be  founded  is  a calcareous  stratified  rock  of  the  Miocene  for- 
mation, with  very  shelving  banks,  covered  with  fine  layers  of  sand 
and  rock  ruins.  The  formation  is  very  variable,  both  as  to  the 
quality  and  hardness  of  the  rock. 

The  water  has  washed  away  the  soft  parts  and  left  the  hard,  so 
that  the  surface  of  the  rock  presents  a series  of  projections  with  the 
hollows  tilled  with  sand  and  fragments ; hence  the  same  arrange- 
ments had  to  be  made  as  if  the  rock  had  been  completely  porous, 
by  substituting  a b^ton  bottom  for  the  natural  soil.  The  submarine 
operations  Avere  as  folloAvs : First,  the  blasting  of  the  rock  ; second, 
the  removal  of  the  sand  and  rock  blasted,  and,  third,  the  laying  of 
the  masonry  on  the  bottom  thus  cleared. 

Two  solutions  of  the  problem. — The  thickness  of  the  banks  and 
their  great  depth  under  water  precluded,  for  the  boring,  any  arrange- 
ment employing  machinery  set  up  above  the  level  of  the  water. 
The  same  circumstances  Avould  have  rendered  the  extraction  of  the 
pieces  of  rock  by  dredges  very  difficult.  Again,  the  sinking  of  b£ton 
under  water  at  such  great  depths  would  have  given  only  mediocre 
results. 

Recourse  must  be  had  to  pneumatic  processes.  Two  solutions 
presented  themselves.  One  was  that  adopted  for  the  construction  of 
the  docks  at  Toulon  and  for  the  basin  at  Saigon.  It  consisted  in  con- 
structing the  masonry  of  the  flooring  and  side  walls  upon  several 


CIVIL  ENGINEERING,  ETC. 


725 

great  floating  caissons  and  producing  by  the  increasing  load  of  this 
masonry  their  gradual  immersion  and  descent  into  the  soil  at  the 
bottom,  then  Ailing  the  working  chamber  with  bet  on  when  the  cut- 
ter had  arrrived  at  the  chosen  bottom  upon  which  the  work  was  to 
be  erected.  This  is  in  reality  the  extension  of  the  process  in  use  for 
the  foundation  of  bridge  piers.  It  is  perfectly  satisfactory  when 
absolute  tightness  is  not  required  in  the  work,  but  this  is  not  the 
case  with  the  dry-dock.  It  is  impossible  to  disguise  the  fact  that 
the  iron  imbedded  in  the  masonry,  the  plates  forming  the  diaphragm 
between  the  upper  masonry  and  the  bdton  Ailing  the  working  cham- 
ber. exclude  precisely  the  conditions  of  homogeneity  and  continuity 
of  the  masses  which  such  constructions  are  expected  to  fulflll.  The 
metal  interposed  must  necessarily  alter  with  time  and  produce  leaks. 
It  is  also  very  difficult  to  spread  upon  such  a great  floating  caisson 
the  increasing  load  of  masonry  in  a manner  sufficiently  uniform  to 
avoid  all  changes  of  form,  and  to  work  without  ever  deviating  from 
a horizontal  plane,  flrst  in  grounding  the  caisson  upon  an  irregular 
bottom,  and  then  in  building  it  upon  a rocky  bottom.  The  changes 
of  form  and  the  Assures  which  they  would  cause  were  particularly 
to  be  feared  at  Genoa,  where  the  immersion  had  to  be  made  in  a part 
of  the  harbor  not  entirely  sheltered  against  the  waves  and  where 
the  blasting  of  the  foundations  presented  great  difficulty.  Another 
solution  must  be  found.  That  which  the  contractors  proposed,  which 
avus  adopted  by  the  technical  commission,  consisted  in  removing  the 
rock  and  laying  the  masonry  under  water  in  great  di\'ing-bells  fur- 
nished with  the  apparatus  necessary  for  rapidly  effecting  the  hori- 
zontal or  \rertical  displacement  of  those  machines  best  adapted  to 
the  boring  and  extraction  of  the  blasted  material  and  the  introduc- 
tion of  new. 

This  process  permitted  the  direct  building  of  the  foundation  upon 
the  prepared  bottom,  avoiding  risks  of  change  of  form  and  of  rup- 
ture in  the  perfectly  homogeneous  and  continuous  masonry,  in  which 
no  portion  of  iron  remained  imbedded.  ItalloAved  the  different  por- 
tions of  the  Avork  to  go  on  independently.  These  Avere  the  moti\”es 
which  decided  the  contractors  to  adopt  this  solution  and  to  construct 
for  realizing  it  : 

First.  A movable  caisson  for  blasting  out  the  rocks. 

Second.  Tavo  other  movable  caissons  for  the  construction  of  the 
walls  for  the  quay  and  basin. 

Third.  A great  floating  caisson  for  the  extraction  of  the  rocks  and 
for  the  construction  of  the  flooring. 

(241)  Caisson  for  blasting  out  the  rocks. — The  blasting  caisson 
(Fig.  148)  is  20  meters  long  and  G.50  meters  Avide.  The  working 
chamber  does  not  differ  from  those  ordinarily  used  for  the  construc- 
tion of  bridge  piers,  except  that  the  Avails  are  lighter,  as  they  do  not 
have  to  bear  the  load  of  the  masonry  above  the  bottom. 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


726 

Pigs  of  iron  placed  between  the  beams  of  the  roof  balance  the 
under  pressure  and  keep  the  caissons  on  the  bottom.  Two  horizontal 
plate-iron  cylinders,  2 meters  in  diameter  and  5.50  meters  in  length, 
are  fixed  above  the  frame  parallel  to  the  transverse  axis  of  the 
caisson  and  in  symmetric  positions  in  respect  to  this  axis.  They  are 
open  at  their  lower  parts.  A tube  connects  one  with  the  other  and 
puts  them  in  communication  with  the  compressed-air  pipes  which 
supply  the  working  chamber.  Water  is  allowed  to  ascend  in  the 
cylinders,  to  fill  them,  when  the  caisson  ’•  kept  at  the  bottom  for 
blasting.  The  water  is  forced  out  by  me?  as  of  compressed  air  when 
the  caisson  is  to  be  raised  and  changed  in  position. 

This  substitution  of  water  for  air  in  the  cylinders,  which  has  for 
effect  the  gradual  augmentation  of  the  water  displaced  by  the  sys- 
tem, can  be  regulated  at  will  and  continued  just  to  that  degree  neces- 
sary for  the  equilibrium  of  the  load,  so  as  to  assure  the  stability  of 
the  caisson  upon  the  bottom  ; the  slightest  effort  then  suffices  to  lift 
the  apparatus.  The  caisson  is  surmounted  by  tAvo  shafts  with  air 
locks  for  the  entrance  of  workmen.  A third  is  reserved  to  add,  if 
necessary,  a lock  for  the  materials  extracted. 

The  caisson  is  suspended  by  twenty-four  chains  to  as  many  jacks 
resting  on  a lieaAry  staging,  which  in  turn  rests  on  tAvo  barges  fur- 
nished with  all  the  apparatus  necessary  for  a rapid  displacement. 

(242)  Boring  apparatus. — The  boring  apparatus  made  by  M.  Sul- 
zer  at  Winterthur,  is  arranged  in  the  following  manner:  The  plat- 
form of  the  caisson  is  divided  lengthwise  into  three  equal  belts  by 
four  double  T-irons,  the  loAver  wings  of  which  serve  as  a rolling 
track  for  three  trunnions  on  rollers.  Each  of  these  trunnions  has  a 
collar  at  its  loAver  part  to  which  one  of  these  boring  machines  is  sus- 
pended by  a joint.  The  trunnion  moves  the  length  of  the  platform, 
the  collar  slightly  unscreAving  along  the  whole  trunnion,  so  that  the 
point  of  articulation  of  the  boring  machine  may  occupy  every  posi- 
tion of  a plane  Avithin  the  limits  of  one  of  the  three  belts,  and  the 
tool  may  also  turn  in  each  of  its  positions  in  all  directions  so  as  to 
pierce  sloping  holes  at  will.  The  boring  machines  are  driven  by 
water  under  pressure  brought  from  an  accumulator  on  the  boat,  by 
jointed  piping  which  descends  along  the  central  shaft,  runs  along 
the  platform,  and  feeds  the  tools  in  all  positions  and  inclinations 
giAren  them.  As  the  boring  progresses  the  boring  tool  is  prolonged 
by  hollow  rods  screwed  together.  The  diameter  of  the  boring  bit  is 
10  centimeters  for  the  holes  exceeding  2 meters  in  depth,  and  (5  cen- 
timeters for  the  others.  Tavo  double-acting  twin  pumps,  furnishing 
water  under  pressure,  are  placed  in  a boat  fastened  to  the  cais- 
sons. They  are  driven  by  two  portable  engines  of  25  horse  power 
each.  The  water,  taken  from  the  sea,  is  driven  into  an  accumulator 
and  kept  under  pressure  by  the  steam  taken  from  the  engine  boilers. 
The  steam  acts  on  the  upper  surface  of  a plate,  fourteen  times  the 


Port  of  Ge 


iio.-iiun^versesecuon  or  uie  movable  caissons  used  fordrilling  the  rock 
pontoons  supporting  the  caisson;  U,  lock  for  the  workmen:  B.  drills < Brandt’: 
pressure  is  conveyed  to  drive  the  boring  machines. 


H.  Ex.  410 — vol  i ix — Fare  page  727. 


Blasting  caissons. 


f\ 


I 


l «‘Pun>ose  of  submarine  blasting.  X,  the  working  chamber;  Y.  the  lightering  chamber;  Z. 
■'  n),  31,  tuo  steam  engines, driving  pumps  feeding  an  accumulator  from  which  water  under 


CIVIL  ENGINEERING,  ETC. 


7L>7 


section  of  the  piston,  which  transmits  directly  to  the  water  the  pres- 
sure of  00  or  70  atmospheres,  necessary  for  boring.  This  arrange- 
ment avoids  the  great  load  which  would  have  to  be  placed  upon  the 
barge  with  an  accumulator  so  weighted  as  to  be  capable  of  giving 
such  a great  pressure.  When  the  boring  of  the  holes  has  been  com- 
pleted*, just  to  the  required  depth,  over  the  whole  surface  covered  by 
the  caisson,  they  are  filled  with  cartridges  or  dynamite  gelatin,  the 
wires  are  attached  to  a floater  which  is  passed  under  the  cutter,  the 


Fig.  149.— Port  of  Genoa.  Transverse  section  of  the  movable  caisson. 

caisson  is  raised  and  moved  by  the  supporting  barges,  and  tire  mines 
exploded  by  an  electric  battery.  By  experience  in  regulating  the 
distance  between  the  holes  and  the  amount  of  the  charges,  they  suc- 
ceeded in  giving  to  the  fragments  of  rock  broken  off  the  dimensions 
most  convenient  for  use. 

(243)  Movable  caisson  for  the  construction  of  the  quay  walls.  (Figs. 
149-150). — These  two  caissons,  which  served  also  for  the  removal  of 


728 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS, 


Fio.  150. — Elevation  and  longitudinal  section  of  the  movable  caissons  used  in  laying  the  masonry  under  water.  X,  the  working  chamber;  Y,  the  lightering  cham- 
ber; Z,  the  pontoons  supporting  the  caisson  ; U,  S,  C,  locks  for  the  men,  materials,  and  be  ton,  respectively. 


poir 


H.  Ex.  410— vol  in— Face  page  729. 


>.3  and  154. 

ock ; for  description  see  p.  729. 


I 

Figs.  155  and  156. 


CIVIL  ENGINEERING,  ETC. 


729 


the  broken  material,  were  20  by  6.50  meters,  and  18  by  5. GO  meters. 
They  were  constructed,  ballasted,  and  suspended  like  the  one  just 
described.  They  were  provided  with  a man  lock,  and  a second  lock 
for  the  removal  of  the  spoil  and  the  introduction  of  the  materials, 
and  a third  for  the  introduction  of  b£ton. 

(244)  At  Rome,  before  the  invention  of  Zschokkd’s  excavation 
lock,  the  spoil  was  removed  through  locks  placed  upon  shafts  0.70 
meter  in  diameter.  These  shafts  were  supplied  with  iron  ladders  in- 
side. serving  in  case  of  need  for  the  removal  of  the  spoil  and  for 
the  use  of  the  workmen.  The  spoil  loaded  into  buckets  of  about  35 
liters,  was  raised  by  an  elevator  fixed  to  the  upper  part  of  the  lock 
and  put  in  motion  by  a cable  transmission. 

The  insufficiency  of  this  method,  especially  for  raising  large 
blocks,  was  immediately  recognized,  and  the  company  put  into  use 
its  newly  invented  excavation  lock,  which  merits  especial  considera- 
tion. It  is  represented  in  Figs.  151-156,  in  the  new  form  which  it 
had  at  the  works  at  Genoa  and  Bordeaux. 

(245)  Description  of  the  excavation  loch. — This  lock  forms  the 
upper  part  of  a shaft  1.05  meters  in  diameter,  having  its  sections 
united  by  external  angle  irons.  A circular  interior  angle  iron,  pro- 
jecting into  the  shaft,  is  placed  at  the  bottom  of  the  lock.  An  iron 
plate  0.90  meter  in  diameter,  surmounted  by  two  frames  supporting 
a turning  bucket,  is  suspended  at  the  end  of  a chain  passing  round 
the  drum  of  an  elevator  placed  at  the  top  of  the  lock.  The  bucket 
and  its  supporting  plate  move  freely  through  the  height  of  the  work- 
ing chamber  and  the  shaft,  but  are  stopped  in  their  upward  move- 
ment by  the  striking  of  the  plate  against  an  india-rubber  ring  which 
lines  the  lower  face  of  the  projecting  angle  iron  below  the  lock. 
At  the  moment  when  this  striking  is  produced  an  automatic  motion 
of  levers  acting  upon  a double  stopcock  puts  the  lock  in  communica- 
tion with  the  outer  air.  The  escape  of  the  compressed  air  produces 
an  increasing  pressure  and  a complete  adhesion  between  the  plate 
and  the  angle  iron.  The  outside  rolling  door,  bordered  with  india- 
rubber,  which  the  interior  pressure  no  longer  holds  against  the  cyl- 
inder, is  opened.  The  bucket  is  turned  toward  the  opening  and  its 
contents  (400  liters)  discharged.  The  bucket  is  then  tipped  back, 
and  the  exterior  door  closed  ; by  a reverse  movement  of  the  stopcock, 
the  communication  bet  ween  the  working  chamber  and  the  lock  is  re- 
established. The  compressed  air  rushes  into  the  lock.  The  equi- 
librium is  again  established  on  both  sides  of  the  moving  plate,  and 
nothing  stops  the  descent  of  the  bucket  into  the  working  chamber. 
The  elevator  is  raised  by  a portable  engine  and  cable,  when  the  local 
conditions  allow  this  mode  of  transmission,  as  was  the  case  at  Rome. 
Elsewhere  the  motion  is  transmitted  from  a Sclimied  motor  fixed 
upon  the  platform  of  the  lock  and  worked  sometimes  by  compressed 
air.  and  sometimes  by  water  under  pressure. 


730 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


This  little  light  lock,  very  easy  to  move,  allowed  the  rapid  removal 
of  very  considerable  quantities,  and  quite  large  blocks  without  re- 
quiring for  its  management  the  presence  of  a single  man  in  the 
compressed  air.  It  was  not  arranged  for  the  passage  of  the  work- 
men who  went  in  easily  through  the  old  entrance,  the  lateral  locks 
for  removing  the  spoil  having  been  taken  away. 

The  new  excavation  lock,  employed  in  its  first  form  ten  years  ago, 
has  been  very  much  improved,  and,  in  view  of  the  works  executed  at 
Bordeaux  and  Genoa,  it  is  placed  in  the  exhibition  (Machinery  Hall) 
with  its  latest  improvements  adopted  in  1888. 

The  chain  drum  is  driven  by  means  of  two  friction  wheels  by  a 
Schmid  -water  motor  taking  its  supply  directly  from  the  city  reser- 
voir situated  100  meters  above  the  sea. 

The  two  caissons  served  not  only  to  introduce  the  bdton,  but  also 
to  lay  the  masonry  and  the  revetment  in  brick  and  cut  stone  of  small 
dimensions.  When  the  hewn  stones  were  of  too  great  dimensions  to 
be  carried  in  through  the  locks  they  were  lowered  outside  by  means 
of  a floating  crane,  the  caisson,  which  had  to  be  removed  for  this 
operation,  was  replaced,  and  the  workmen  found  in  the  working 
chamber  the  stones  to  be  set  up. 

(24G)  Great  floating  caisson. — The  great  floating  caisson  shown 
in  Fig.  157  is  intended  for  raising  the  fragments  of  rocks  made  by 
the  explosion  of  the  mines  just  described,  and  for  laying  the  btfton 
flooring.  It  is  38  meters  long  and  32  meters  wide,  that  is,  1,210  me- 
ters of  surface.  These  dimensions  were  required  on  account  of 
those  of  the  flooring.  The  widest  of  the  two  floors  is  36  meters,  that 
is,  2 meters  less  than  the  length  of  the  caisson. 

The  caisson,  which  is  now  floating  in  the  port  of  Genoa,  consists 
of  three  essential  parts: 

First.  The  working  chamber,  2 meters  high,  surrounded  by  two 
tight  plate-iron  envelopes,  one  vertical,  forming  the  exterior  walls, 
the  other  inclined,  covering  the  interior  faces  of  the  braces  from  the 
roof  to  the  cutter. 

Second.  The  equilibrium  chamber,  which  rises  above  the  first  to  a 
height  of  3 meters.  It  is  completely  enveloped  with  plate  iron  and 
traversed  by  shafts  giving  access  to  the  working  chamber. 

Third.  The  iron  reservoirs  or  regulating  pits,  which  rest  upon  the 
equilibrium  chamber  without  communicating  with  it,  and  which 
are  open  at  their  upper  parts  above  the  level  of  the  sea.  These  pits 
are  four  in  number.  Two  of  them  extend  the  whole  length  of  the 
caisson  parallel  to  its  walls  and  1 meter  from  the  latter.  They  are 
3 meters  wide  and  8.60  meters  high.  The  two  others,  at  right  angles 
to  the  first,  are  placed  symmetrical ly  with  respect  to  the  shorter  axis 
of  the  caisson.  They  are  also  8.60  meters  high,  and  their  width  is 
3.50  meters.  These  four  pits  are  connected,  and  the  rectangular 


Port  of  Genoa. 


Fig.  157.— Great  floating  caisson  used  in  laying  the  flooring  of  dock  No.  2;  transverse  section. 

0.70  meter;  C,  Shaft  for  the  b£tou,  0.45  meter 


H.  Ex.  410 — vol  in — Face  page  730. 


I 


srior  diameter. 


CIVIL  ENGINEERING,.  ETC. 


731 


central  portion  formed  by  their  interior  walls  communicates  by  a 
pipe  with  the  sea.  The  walls  and  braces  of  the  four  pits  form  the 
framework  to  support  the  service  bridges  and  stagings  which  lead 
to  the  different  air  locks,  and  carry  the  tracks,  cranes,  etc.,  required 
for  the  handling  of  the  excavations  and  the  materials. 

Arrangements  have  been  made  for  filling  the  equilibrium  cham- 
ber with  water  or  compressed  air,  as  may  be  necessary,  and  for 
changing,  at  will,  the  level  of  the  water  in  the  regulating  pits,  which 
may  even  be  completely  emptied  by  means  of  pumps.  The  appara- 
tus is  thus  maintained  in  equilibrium  under  all  circumstances  (Figs. 
158-161).  The  caisson  unloaded  draws  2.55  meters,  making  the  ceil- 
ing of  the  working  chamber  0.55  meter  below  the  level  of  the  sea. 
It  is  brought  into  the  condition  of  stability  required  for  working,  by 
placing  enough  iron  ballast  between  the  braces  and  over  the  ceiling, 
to  make  it  sink  5.10  meters,  which  allows  the  ceiling  of  the  upper 
chamber  to  be  10  centimeters  out  of  water.  The  immersion  will 
go  on  increasing  as  water  enters  the  equilibrium  chamber  and  into 
the  regulating  pits,  unless  compressed  air  is  introduced  into  the 
working  chamber. 

If  one  equilibrium  chamber  is  filled  with  water,  and  if  the  central 
tank  is  maintained  in  communication  with  the  sea  by  the  pipe,  of 
which  we  have  heretofore  spoken,  the  cutter  may  be  lowered  to  the 
reference  ( — 8)  even  if  compressed  air  is  introduced  into  he  working 
chamber.  We  may  then,  if  the  working  chamber  remains  filled 
with  air,  lower  the  cutter  to  the  reference  — 0,  by  allowing  the  water 
to  rise  1.15  meters  in  the  regulating  pits:  and  to  the  reference  —11.50 
meters  if  the  water  level  in  these  pits  is  brought  to  2.50  meters  below 
the  sea,  etc. 

To  raise  the  caisson  rapidly  it  is  sufficient  to  pass  compressed  air 
from  the  working  chamber  into  the  equilibrium  chamber  and  to 
diminish  thus  the  load  of  water  in  the  latter,  taking  care  always  to 
open  the  discharging  orifices  made  in  the  walls  of  the  pits  so  as  to 
lower  the  level  of  the  water  which  they  contain  as  the  caisson  rises. 
But  this  process,  which  prevents  access  to  the  working  chamber,  is 
only  applicable  if  we  wish  to  obtain  a rapid  rise.  If,  on  the  con- 
trary, it  is  required  to  raise  the  caisson  while  the  work  is  going  on 
in  the  chamber  we  must  empty  first  the  regulating  pits  bv  means  of 
pumps  and  then  begin  by  foiling  out  the  water  contained  in  the 
equilibrium  chamber  by  means  of  compressed  air. 

To  facilitate  these  different  operations  several  great  pipes,  fur- 
nished with  stoppers,  have  been  arranged  in  the  equilibrium  cham- 
ber above  the  braces.  These  allow  the  introduction  of  sea  water  or 
provide  for  its  expulsion  by  conqu’essed  air.  The  air  from  tin1 
working  chamber  is  passed  into  the  equilibrium  chamber  through  a 
valve  in  a pipe  which  passes  at  the  height  of  the  service  bridge- 


732  UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 

Port  of  Genoa.  Positions  of  the  caisson  in  its  different  states  of  eqcilibricu,  scale  4J0. 


Fig.  158.— Without  ballast. 


4 

5 







_ ___ 

— 

■ 

—TX  _ 

1 

-- 

' r r-  ■///’T-’  v//y/7  /?/  Fy/7//y/y  »?/////  'i " 

( air-  convpr 

^-5^,  * ^ J v/  % rtf- " ’T^^TffTTi 

^r.  ■* 

•i!" 

oo 


Pigs.  160  and  161.—  Caissons  at  work. 


y 


CIVIL  ENGINEERING,  ETC. 


733 


roadway.  Another  pipe  allows  air  to  be  sent  directly  from  the  com- 
pressors into  the  equilibrium  chamber.  The  regulating  pits  are  put 
in  communication  with  each  other  and  with  the  sea  by  pipes  0.45 
meter  in  diameter  furnished  with  cocks  operated  on  the  service 
bridge. 

The  weight  of  ballast  and  the  dimensions  of  the  pits  depend  on  the 
depth  at  which  the  work  goes  on  with  a stable  caisson.  At  Genoa 
the  arrangements  were  made  for  a depth  of  from  8 to  14.50  meters. 

To  be  able  to  remove  without  too  much  difficulty  the  fragments  of 
rock  caught  under  the  cutter  a file  of  screw-jacks  is  arranged  in  the 
working  chamber  upon  which,  when  necessary,  the  weight  of  the 
caisson  may. rest.  These  jacks  rest  on  two  open  beams  fixed  under 
the  ceiling,  parallel  to  the  longitudinal  walls  which  they  must  lift, 
and  at  4 meters  distance  from  them. 

The  rock  fragments  are  taken  out  by  six  excavation  locks.  The 
bdton  is  spread  along  the  whole  length  of  the  flooring  in  superposed 
layers  of  0.50  meter  thickness.  Little  brick  Avails  are  built  as  this 
goes  on  along  the  longitudinal  borders  of  the  mass,  which  prevent 
the  bdton  from  running  over.  In  the  transverse  direction,  on  the 
contrary,  the  bdton  is  left  to  take  its  natural  slope.  The  walls  would 
be  useless  there,  besides  breaking  the  homogeneity  of  the  mass. 

(247)  Mrthodof  laying  the  flooring.— When  the  b£  ton  has  been  spread 
over  a thickness  of  50  centimeters  the  caisson  is  vertically  raised  and 
a neAV  layer  placed  above  the  preceding.  When  a first  mass  1.50  me- 
ters thick  has  been  thus  deposited  in  three  superposed  layers,  the 
apparatus  is  moved  the  whole  of  its  width  in  the  longitudinal  direc- 
tion of  the  flooring,  and  grounded  so  that  the  longitudinal  cutter 
shall  come  to  rest  at  the  foot  of  the  cross  slope  of  the  first  mass  at  S, 
(see  Fig.  102).  A layer  of  50  centimeters  is  then  deposited,  the  cais- 
son is  then  raised,  and,  by  a slight  longitudinal  displacement  in  the 
contrary  direction  from  the  preceding,  the  cutter  is  brought  to  touch 
the  slope  of  the  first  mass,  no  longer  at  its  foot,  but  50  centimeters 
abo\'e  it  (at  the  point  2).  A second  layer  is  then  spread  upon  the 
first,  taking  care  to  fill  up,  above  the  cutter,  the  little  triangular  prism 
50  centimeters  high  formed  by  the  two  transverse  slopes,  between 
Avliich  the  cutter  is  placed  in  its  preceding  position.  The  caisson  is 
again  raised  50  centimeters  high,  moved  lengthwise,  a third  layer  is 
spread,  and  at  the  same  time  the  second  little  prism  is  filled  up. 

We  haAre  thus  a second  mass  1.50  meters  thick  joined  to  the  first, 
and  the  caisson  is  then  moA7ed  to  commence  a third  in  the  same  man- 
ner. When  the  layer  of  1.50  meters  extends  continuously  the  whole 
length  of  the  flooring  the  same  operations  are  gone  through  with,  by 
successive  displacements  upon  this  bed.  as  were  previously  made  on 
the  rocky  bottom.  But  care  must  be  taken  that  the  new  positions 
of  the  caisson  should  not  be  directly  over  the  preceding,  in  order  to 


734 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


have  a series  of  little  triangular  transverse  prisms  to  he  filled  up 
under  the  cutter,  etc.  We  thus  obtain  a homogeneous  and  perfectly 
tight  flooring. 


Fig.  162.— Method  of  laying  the  flooring  of  a basin.  The  numerals  1,  2,  8,  l1,  21,  3l,  indicate  the  dif- 
ferent positions  of  the  cutting  edge  of  the  caisson;  the  letters  Si,  S2,  S3;  SV,  S1*,  represent  the  triangu- 
lar prisms  of  b£ton  placed  under  water,  corresponding  to  the  respective  positions  of  the  cutting  edge 
2,  3;  1',  2',  8'. 

In  order  not  to  allow  the  caisson  to  he  floating  during  these  opera- 
tions it  is  supported  upon  two  rows  of  jacks  resting  upon  iron  plates 
placed  on  the  layer  of  bdton  previously  spread. 

(248)  Supply  of  compressed  air,  etc. — The  air-compressors,  which 
supply  the  pneumatic  apparatus  above  described,  are  placed  011  the 


Port  op  Genoa.  Qcai  des  Graces.  Quay  wall  in  arcades. 


-=1 


Fig.  163.— Longitudinal  section  of  one  of  the  centers. 

land,  in  a shop,  by  the  side  of  the  four  150  horse  power  engines  which 
drive  them.  The  supply  pipes  which  lead  to  each  caisson  are  placed 
on  rafts.  These  pipes  are  made  of  sheet  iron,  with  india  rubber 
joints,  so  as  to  prevent  rupture  from  their  constant  working  due  to 
the  motion  of  the  waves. 


CIVIL  ENGINEERING,  ETC. 


735 


The  free  air  spaces  are  lighted  by  Gramme  arc  lights,  and  the  cais- 
sons by  incandescent  lamps.  The  boilers  are  placed  in  the  same 
shop  as  the  compressors. 

A system  of  electric  bells  puts  the  caissons  in  communication 
with  the  engine  shops,  and  informs  the  engineer  of  the  quantity  of 
air  requisite,  by  which  he  regulates  the  working  of  tlxe  compressors. 

(249)  Centers  of  the  arches  for  the  Quai  des  Graces. — The  spring- 
ing line  of  the  arches  between  the  piers  of  the  Quai  des  Graces  is  at 


Fio.  164. — Details  of  the  iron  centers.  Radius  of  the  upper  plate,  R|  =15.475  meters;  radius  of  the 

lower  plate,  R2=  14.175  meters. 


the  reference  —0.20,  and  the  construction  of  these  arches  required  the 
use  of  quite  solid  centers,  as  the  rise  is  reduced  to  1.40  meters  for  a 
span  of  12  meters.  It  was,  therefore,  very  difficult  to  find  a type  of 
center  which  could  be  set  up  above  the  level  of  the  water.  In  order 
to  find  a support  it  would  have  been  necessary  to  go  down  0 meters 
below  this  level. 

The  contractor  therefore  decided  to  construct  a special  center 
adopted  for  these  exceptional  conditions.  It  is  formed  (Fig.  163) 


736 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


of  curved  beams  of  13.90  meters  span,  having  their  lower  plates 
curved  exactly  to  the  form  of  the  extrados  of  the  arch  to  be  con- 
structed, and  they  had  to  be  arranged  so  as  to  coincide  with  this 
curve  when  placed.  The  lattice  beams  are  arranged  so  that  long 
bolts  could  be  placed  in  line  with  the  verticals,  directed  along  the 
plain  joints  of  the  arch  (Fig.  1G4),  and  having  their  heads  borne  by 
the  upper  plate  on  the  beams.  The  nuts,  screwed  to  the  bases  of 
these  bolts,  carried  pairs  of  channel  iron  beams,  laid  along  the  gener- 
atrixes  of  the  intrados  of  the  arch  so  as  to  support  the  plates  serving 
as  bolsters.  Upon  these  plates,  suspended  instead  of  supported,  the 
arches  were  constructed.  To  remove  the  center,  the  bolts  were  taken 
away  after  unscrewing  the  nuts.  The  system  of  channel  iron  beams 
and  intrados  plates  were  then  placed  upon  a raft,  by  which  they  were 
taken  away  to  be  set  up  again ; at  the  same  time  the  lattice  beams 
were  removed  by  a floating  crane  and  again  placed  between  the 
piers,  which  had  to  be  united  with  a new  arch. 

Experience  has  shown  this  new  arrangement  of  centers  to  have 
given,  in  all  respects,  satisfactory  results. 

Chapter  XXVIII. — Foundation  of  the  jetties  at  La  Pallice, 
the  port  of  Rochelle. 

(250)  The  foundations  of  the  two  jetties  in  the  outer  harbor  of  La 
Pallice  (Fig.  1G5)  had  to  be  laid  below  the  level  of  the  lowest  tide. 


Fig.  165  —Port  of  Rochelle.  Plan  of  the  outer  harbor  of  La  Pallice. 


The  specifications  required  them  to  be  made  of  great  blocks  of  ma- 
sonry, 20  meters  long  by  8 broad,  separated  by  an  interval  of  2 me- 
ters and  carried  up  to  the  level  of  1.50  meters  ; the  choice  of  methods 
for  carrying  out  the  work  was  left  entirely  to  the  contractors. 

Above  this  series  of  blocks  arose  the  body  of  the  jetty,  which  was 
carried  over  the  spaces  between  the  blocks  by  little  segmental  arches 
of  3 meters  span. 

The  constructors,  MM.  Zschokke  and  Terrier,  made  use  of  mov- 
able caissons  for  the  foundation  of  these  blocks;  the  spaces  between 
the  blocks,  which  it  was  afterwards  decided  to  fill  up,  was  accom- 
plished by  a special  apparatus  which  will  hereafter  be  described. 


\ 


» 


737 


CIVIL  ENGINEERING,  ETC. 

(251)  Process  adopted  for  the  construction  of  the  blocks. — As  the 
blocks  had  to  be  built  on  the  coast,  without  shelter  against  the  sea, 
and  especially  against  the  southwest  gales,  the  contractors  could  not 
employ  the  usual  system  of  caissons,  and  build  upon  the  interior 
flooring  of  the  caisson,  which  the  sea  would  have  carried  away  and 
destroyed.  They  therefore  made  use  of  the  movable  caissons  which 
they  had  successfully  employed  at  St.  Malo;  by  their  use  they  were 
able  to  lay  the  foundations  dry  af  sea,  without  leaving  a particle  of 
iron  in  the  masonry;  they  were  able  to  lay  twenty-four  monolithic 
submarine  blocks  with  1G0  meters  of  surface,  amounting  to  1,150 
cubic  meters  each. 

(252)  Description  of  the  caissons  and  air  locks. — Two  similar  iron 
caissons  were  built  by  MM.  Baudet  <fe  Donon,  22  meters  long  by  10 
meters  wide,  with  two  superposed  compartments  (Figs.  1GG  and  1G7). 


Port  op  Rochelle.  Outer  Harbor  op  La  Pallice.  Caissons. 


The  lower  compartment  was  the  working  chamber,  1.80  meters  high, 
and  the  upper  one  the  equilibrium  chamber,  2 meters  high,  and  com- 
pletely tight ; a platform  was  placed  on  the  latter  which  carried  a 
scaffolding  7 meters  high,  supporting  a second  platform  1G  by  4 me- 
ters. Four  locks  and  shafts  led  from  the  platform  to  the  working 
chamber.  Two  of  these  passages  carried  the  ordinary  air  locks,  and 
two  others  served  for  the  discharge  of  the  excavations  and  the  intro- 
duction of  the  cut  stone. 

At  Rochelle  the  caisson  worked  easily  at  several  hundred  meters 
from  the  shore,  and  the  waves  during  the  tempests  passed  over  the 
scaffolding.  The  winches  of  the  locks  could  not,  therefore,  be  driven 
by  portable  engines  and  cables,  hence  Schmid  motors  were  used, 
supplied  by  the  compressors  set  up  on  shore.  The  caissons  weighed 
H.  Ex.  410— VOL  in 47 


738 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


110  tons  each.  They  carried  between  the  braces  and  on  the  lower 
platform  a permanent  load  of  220  tons  of  masonry.  They  were  set 
up  on  the  shore,  moved  down  on  rollers  at  low  tide  to  the  bottom  of 
an  inclined  plane,  launched  at  the  next  high  tide,  and  towed  near 
to  the  grounding  place.  The  draught  of  water,  with  the  equilibrium 
chamber  filled  with  air  and  the  working  chamber  filled  with  water, 
was  then  3.30  meters.  The  grounding  was  an  operation  always  deli- 
cate and  sometimes  dangerous.  It  was  necessary  to  go  down  exactly 
upon  the  location  of  the  block  to  be  constructed,  against  the  waves, 
and  especially  against  strong  currents.  It  was  anchored  to  six  fixed 
points,  one  of  which  Avas  furnished  by  the  jetty  behind,  and  five  others 
by  buoys  strongly  anchored.  The  anchoring  lines  passed  over  the 
grooves  of  pulleys  fixed  above  the  upper  platform  and  terminated 
at  winches  placed  on  the  platform.  By  hauling  and  letting  go  with 
these  winches  the  position  of  the  caisson,  and  its  alignment  were 
regulated. 

The  height  of  the  water  above  the  bottom  at  low  tide  was,  for 
the  first  blocks,  below  the  draught  of  the  floating  caisson.  It  was 
sufficient  then  to  let  it  go  down  with  the  tide.  When  it  struck  upon 
the  bottom  the  valves  were  opened,  giving  access  to  the  water  in  the 
equilibrium  chamber,  and  the  surcharge  prevented  the  caisson  from 
rising  with  the  tide. 

The  depth  increasing  as  the  work  advanced,  the  low  water  did  not 
bring  the  cutter  to  touch  the  bottom.  In  this  case  the  valves  were 
opened  when  the  caisson  was  lowered,  and  the  entry  of  the  water 
into  the  equilibrium  chamber  produced  the  grounding. 

The  load  was  then  more  than  sufficient  to  fix  the  caisson  on  the 
bottom,  but  a new  load  was  necessary  to  balance  the  under  pressure 
of  400  tons,  produced  by  the  introduction  of  compressed  air  in  the 
working  chamber,  and  to  assure  the  stability  of  the  apparatus.  This 
surcharge  of  about  220  tons  was  given  by  cast-iron  ballast  which 
was  stowed  upon  the  upper  platform. 

(253)  Work  in  the  caisson.— The  first  care  of  the  workmen  going 
into  the  working  chamber  was  to  put  the  caisson  on  a level  by  dig- 
ging at  first  under  the  highest  portions  of  the  cutting  edge. 

They  then  proceeded  to  remove  the  upper  layers  of  the  bottom 
just  to  the  limestone  bed  which  was  judged  proper  to  serve  as  the 
foundation  of  the  block. 

The  operation  of  raising  the  caisson  during  the  laying  of  the 
masonry  was  done  with  the  aid  of  twenty-four  great  screw-jacks 
with  steel  rods  1.80  meters  long  and  0.10  meter  in  diameter  (Figs.  167 
and  1 68).  These  rods  passed  through  brass  nuts  set  up  on  the  smaller 
bases  of  reversed  plate-iron  cones,  the  larger  bases  being  riveted 
to  the  ceiling  of  the  working  chamber.  The  rods  were  in  line  par- 
allel to  the  wall  and  1.50  meters  from  it.  The  lower  extremity  ter- 
minated in  the  form  of  a hemisphere,  carried  in  a hollow  of  the  same 


739 


CIVIL  ENGINEERING,  ETC. 


form  in  a cast-iron  plate  resting  on  the  masonry,  which  thus  avoided 
all  rigid  connection  between  the  suspending  pieces  of  the  rod  and 
the  plate. 

(254)  When  the  masonry  was  commenced  the  twenty-four  jacks, 
having  been  raised  to  the  end  of  their  course,  had  their  plates  0.80* 
meter  above  the  ground.  A layer  of  masonry  0.80  meter  thick  could 
then  be  laid.  They  then  took  the  support  on  this  layer  to  raise  the 
caisson.  As  there  was  to  be  overcome  in  this  first  operation  not 
only  the  weight  of  the  apparatus,  but  the  friction  of  its  walls  in  the 
ground,  they  worked  at  the  same  time  as  the  screw-jacks,  six  hy- 
draulic jacks  of  30  tons  each.  The  caisson  being  thus  raised  0.40  me- 
ter they  kept  as  points  of  support  one  jack  out  of  two,  that  is  twelve 
in  all,  and  took  away  the  other  twelve  jacks  to  build  0.40  meter  of 
height  under  their  plates  (Figs.  167  and  168).  They  then  carried  the 


Fiq.  167.— Transverse  section. 


Fig.  168. — Longitudinal  section. 
Caisson  resting  on  jacks. 


caisson  upon  these  twelve  jacks,  raised  it,  and  then  placed  the  twelve 
others  to  lay  the  masonry  under.  They  had  thus,  around  one  block, 
and  just  to  the  walls,  a continuous  belt  of  masonry  1 meter  thick  and 
0.40  meter  high.  By  a double  working  of  the  jacks  identical  with 
the  preceding,  they  raised  the  caisson  again  0.40  meter  and  carried 
the  height  of  the  surrounding  belt  to  0.80  meter  (Figs.  167  and  168). 
They  then  filled  with  masonry  the  portions  within  the  belt,  which 
completed  the  second  course  of  80  centimeters.  They  proceeded  in 
the  same  manner  until  the  block  rose  to  the  reference  1.50  meters. 

(255)  High  waves  interrupted  the  work  sometimes  for  several 
weeks,  during  which  the  caisson,  exposed  to  the  tempests,  had  to 
rest  upon  its  twenty-four  jacks.  First,  they  limited  themselves  to 
removing  the  under  pressure  and  allowing  the  water  to  come  into 
the  working  chamber,  and  placed  a number  of  struts  between  the 


HO  UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 

walls  of  the  caisson  and  the  partly  finished  block.  Experience  hav- 
ing shown  that  these  precautions  were  insufficient,  they  built  upon 
the  block  four  great  pillars  of  masonry  reaching  up  to  the  ceiling, 
upon  which  the  caisson  rested  during  the  interruptions  of  the  work. 

They  worked  night  and  day  in  the  caissons  (except  during  the  in- 
cessant stoppages  caused  by  heavy  seas).  An  average  of  eight  hours 
out  of  the  twenty-four  was  used  for  laying  the  masonry,  the  sixteen 
others  to  raise  the  caisson  and  to  carry  the  stone  into  the  working 
chamber.  Fifteen  masons  worked  in  the  caisson,  with  thirty  labor- 
ers, laying  50  cubic  meters  of  masonry  per  day.  These  hands  did 
not  include  those  employed  on  the  service  bridge  for  carrying  mate- 
rials and  for  the  preparation  of  the  mortar  on  shore.  The  caissons 
were  raised  by  sixty  men,  forty-eight  to  work  the  twenty-four  jacks, 
and  twelve  for  the  six  hydraulic  jacks.  It  took  on  an  average  one 
and  three-quarter  hours  to  raise  the  caisson  0.40  meter. 

(250)  Displacement  of  the  caisson. — When  a block  was  finished 
they  waited  to  the  next  high  tide  to  disengage  the  caisson.. 

The  reference  of  the  top  of  the  block  being  1.50  meters  and  that 
of  the  high  tide  5.40  meters,  with  a draught  of  water  of  3.30  meters, 
there  was  a margin  of  about  0.60  meter  for  the  grounding. 

The  operation  of  displacement  consisted  in  withdrawing  the  cast- 
iron  ballast,  which  was  deposited  upon  the  boat,  in  replacing  the  six 
anchorages  at  low  tide,  and  in  driving  out  the  water  from  the  equi- 
librium chamber  and  allowing  the  caisson  to  rise  with  the  tide.  At 
the  moment  of  high  tide  they  pulled  with  the  winches  upon  the 
anchorage  chains  toward  the  open  space,  and  they  let  go  on  the  op- 
posite side  until  the  caisson  was  brought  over  its  new  anchorage. 
They  then  repeated  the  operations  already  described  for  immersion. 

(257)  The  difficulty  of  this  operation  arose  because  the  caisson  had 
to  float  nine  hours,  often  in  the  night,  from  the  moment  when  it  lost 
its  support  upon  the  finished  block  to  the  moment  Avhen  the  follow- 
ing low  tide  allowed  it  to  be  grounded  anew.  If  a tempest  arose 
when  the  caisson  did  not  cover  the  block  they  could,  although  not 
without  risk,  precipitate  its  immersion,  but  the  danger  would  be 
very  much  greater  if  a sudden  change  of  weather,  as  was  often  the 
case  in  these  regions,  had  overtaken  the  caisson  floating  at  the  mo- 
ment when  one  could  not  disengage  it  from  the  block  nor  ground  it 
again  upon  it,  hence  they  did  not  move  the  caisson  except  when  the 
weather  appeared  to  be  favorable  and  the  tide  sufficiently  high.  It 
was  not  possible  always  to  fulfill  this  double  condition,  except  by 
waiting  five  or  six  weeks,  during  which  the  materials  were  unused 
and  the  workmen  idle. 

These  operations  of  incontestible  boldness  were  repeated  twenty- 
four  times. 

(258)  Access  to  the  caisson  was  from  the  jetty,  which  was  built  as 
the  first  blocks  were  laid,  and  by  a service  bridge  constructed  upon 
the  last  blocks  not  yet  finished. 


CIVIL  ENGINEERING,  ETC. 


741 


This  service  bridge  rested  on  an  iron  framework  having  its  up- 
rights of  channel  iron  fixed  in  the  masonry.  It  was  constructed  as 
light  as  possible,  so  as  to  not  offer  much  resistance  to  the  waves,  but 
at  the  same  time  solid  enough  to  give  passage  to  the  cars  loaded  with 
materials  for  the  work.  Over  this  bridge  passed  the  electric  wires 
for  lighting,  the  two  air  pipes  which  supplied  the  working  chamber, 
and  the  air  for  driving  the  little  motors  of  the  excavation  locks. 

The  level  of  this  service  bridge  was  constant,  while  the  platform 
surrounding  the  locks  varied  according  to  the  height  of  the  caisson 
on  the  block.  When  the  platform  was  sensibly  higher  than  the 
service  bridge  the  two  were  joined  by  a safety  planking,  carrying 
rails  upon  which  the  little  cars  were  raised  by  means  of  a winch 
driven  by  one  of  the  little  compressed-air  motors  of  the  locks  (Fig. 
165). 

(259)  Removal  of  the  submarine  rocks  of  the  outer  harbor  of  La 
Pallice. — After  an  ineffectual  attempt  to  make  use  of  the  great  cais- 
son for  the  purpose  of  removing  the  rocks  of  the  outer  harbor,  the 
contractors  proposed  to  close  the  entrance  to  this  harbor  by  sinking 
four  new  blocks,  also  to  close  all  the  spaces  between  the  blocks 
already  sunk,  and  thus  establish  an  immense  cofferdam  within 
which  120,000  meters  of  rock  could  be  removed  by  the  ordinary  pro- 
cesses. These  four  blocks  were  accordingly  sunk,  and  the  wall 
above  them  raised  to  the  reference  + 10  meters,  i.  e.,  15  meters  above 
the  foundation. 

(260)  The  junction  of  the  blocks. — The  principal  difficult}’ of  the 
work  consisted  in  closing  under  water  the  openings  which  had  been 
left  between  the  blocks,  which  the  debris  rolled  in  by  the  sea  had 
already  in  part  obstructed.  These  openings  were  of  a plain  rectan- 
gular section  in  the  straight  portions  of  the  jetties.  Their  width 
varied  from  2 to  3 meters,  according  to  the  position  which  had  been 
given  to  the  caissons  in  grounding  them.  In  the  curved  portions 
of  the  northern  jetty  the  foundation  blocks,  constructed  along  a 
polygonal  plan,  left  between  them  trapezoidal  spaces.  The  condi- 
tions of  tightness,  which  it  was  absolutely  necessary  to  satisfy,  did 
not  allow  the  bdton  to  be  run  in  under  water,  which  would  have 
never  reached  the  solid  foundation,  and  which,  besides,  would  not 
have  set  against  the  sides  of  the  block  already  covered  with  marine 
vegetation.  The  little  sides  of  the  openings  could  not  be  closed  by 
panels  to  make  an  inclosure  open  at  the  top  which  could  be  pumped 
out.  The  panels  would  not  have  reached  the  bottom  through  the 
deposits  which  covered  it,  and  the  little  open  inclosure  would  have 
been  constantly  broken  in  upon.  Again,  the  irregularity  in  form  of 
these  spaces,  the  force  of  the  current  which  passed  through  them, 
and  the  entire  absence  of  all  shelter  from  the  sea  were  sufficient  mo- 
tives to  prevent  the  employment  of  a movable  caisson,  which  M. 
Zschokke  had  previously  employed  with  complete  success  for  the 


742 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


junction  of  the  St.  Malo  locks  in  the  Seine.  A new  process  must 
he  found  which  would  resist  the  sea,  and  allow  the  openings  to  be 
filled  with  masonry,  laid  dry,  after  the  spaces  between  the  blocks 
had  been  cleaned  out. 

(261)  The  contractors  proposed  the  following  arrangement,  which 
was  approved  by  the  engineers.  They  converted  each  opening  into 
a little  caisson  formed  by  the  two  walls  of  the  block  to  be  united,  by 
the  arch  originally  provided  between  these  blocks,  and  by  two  lat- 
eral iron  panels  (Fig.  169). 

At  the  reference  of  the  springing  line  of  the  arch  (+  2 meters) 
the  mass  of  the  jetties  was  behind  the  faces  of  the  blocks.  It  was 
necessary  in  order  to  have  a complete  ceiling  to  prolong  the  arches 


Method  of  closing  the  space  between  the  blocks  — Putting  in  the  panels. 


until  they  were  vertically  over  these  walls,  and  to  load  them  3 me- 
ters high  with  the  quantity  of  masonry  necessary  to  resist  the  under 
pressure.  They  made  a vertical  cylindrical  opening  in  the  arch 
0.70  meter  in  diameter,  by  prolonging  which  they  embedded,  above 
the  extrados,  a plate-iron  collar  and  angle  irons  serving  for  a passage 
of  a shaft  0.70  meter  in  diameter  (Fig.  169).  They  raised  the  jetty 
to  the  reference  + 8,  leaving  the  interior  of  the  mass  above  the 
aperture  for  the  lock  placed  upon  its  shaft. 

Two  strong  beams  placed  at  the  same  reference,  +8,  across  the 
masonry,  carried  two  winches,  each  placed  perpendicularly  to  the 
two  wall  faces  (Fig.  170).  These  winches  served  to  handle  the  iron 
panels  which  completed  the  working  chamber.  The  panels  were 
formed  of  horizontal  elements  of  plate  iron  with  India-rubber  bands 
between  them,  and  angle  irons  0.40  and  0.50  meter  high,  which 
could  be  put  together  anywhere  by  bolts  (Fig.  172).  These  elements 
were  curved  at  their  extremities,  which  rested  upon  the  longitudinal 


CIVIL  ENGINEERING,  ETC. 


743 


walls  of  the  two  blocks.  The  upper  element  was  also  curved  upon 
its  longitudinal  upper  face  so  as  to  completely  close  upon  the  ma- 
sonry wall  above  the  arch.  The  angle  irons  of  the  elements  were 
pierced  with  holes  for  the  attachment  of  tie-rods  with  turn-buckles 
(Fig.  170),  which  served  to  bring  together  and  tighten  the  panels 

Walls  under  the  panels. — Method  op  holding  the  panels. 


upon  the  two  opposite  faces.  Two  panels  were  made  for  each  arch ; 
they  were  placed  face  to  face,  with  a number  of  elements  determined 
by  the  vertical  distance  between  the  intrados  of  the  arch  and  the 
surface  of  the  layer  of  the  detritus  which  obstructed  the  bottom  of 
the  opening.  The  panel  thus  prepared  was  suspended  by  tackles 


Fig.  171. — Transverse  section.  Fig.  172.— Longitudinal  section. 

from  the  two  winches,  lowered  at  low  tide,  and  maintained,  at  first, 
at  the  height  necessary  for  the  angle  irons  and  their  lower  elements  to 
be  placed  a little  below  the  intrados  of  the  arch,  and  a little  above 
the  low-tide  level.  Men  went  into  the  opening  and  placed  the  two 


744 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


tie-rods  of  tlie  lower  angle  iron  without  tightening  them  too  much. 
Then  the  two  panels  were  lengthened  by  the  height  of  the  next  ele- 
ment. The  second  set  of  angle  irons  was  put  on  under  the  intrados, 
and  two  new  tie-rods  were  placed.  They  proceeded  in  the  same 
manner  until  the  lower  angle  iron  and  the  panels  touched  bottom, 
and  they  had  already  a resistance  sufficient  to  withstand  the  cur- 
rents and  the  rising  tide  or  even  the  waves  if  the  sea  became  rough. 
At  the  following  tide  they  tightened  the  tie-rods  of  the  upper  ele- 
ments and  made  with  clay,  quick  setting  cement,  and  hemp,  a tight 
joint  between  the  parts  of  the  first  element  and  the  faces  of  the 
blocks;  they  drove  out  the  water  by  introducing  compressed  air  un- 
der the  arch,  and  then,  working  in  the  compressed  air,  they  put  on 
the  lower  elements  and  luted  the  joints. 

(202)  They  thus  arrived  at  the  bottom  of  the  panel;  then  they  came 
to  a mass  of  stones  and  debris  coming  from  the  construction  of  the 
blocks.  They  united  this  ddbris  together  below  the  panel  by  sacks 
of  quick -setting  cement,  and  then  began  to  clean  out  the  space,  at  the 
same  time  holding  the  ddbris  under  the  panel,  and  on  the  outside,  by 
little  walls  made  with  cement  (Fig.  171).  These  little  walls  thus 
formed  the  prolongations  of  the  panels  and  allowed  the  men  to 
descend  to  the  foundations  of  the  block,  and  to  begin  laying  the  ma- 
sonry there. 

As  the  masonry  rose,  the  tie-rods  which  were  met  were  replaced 
by  short  iron  rods,  curved  and  embedded  in  the  masonry,  and  con- 
nected to  the  flanges  of  the  panels  by  a hook  driven  upward  so  as 
to  be  able  to  be  pushed  down  and  thus  release  the  panel. 

When  they  arrived  at  the  reference  1 meter  they  stopped,  all  the 
hooks  were  pushed  down  by  bars,  the  upper  tie-rods  taken  off,  and 
the  panels,  becoming  free,  could  be  used  in  another  place. 

The  rest  of  the  space  under  the  arch  was  finished  in  the  open  air 
at  low  tide. 

The  construction  of  these  great  blocks  began  in  May,  1884,  and 
terminated  in  June,  1888.  During  this  time  the  two  caissons  con- 
structed twenty-four  blocks. 

The  depth  at  which  the  blocks  were  laid  varied  from  the  reference, 
—0.76  to  —5.35  meters,  and  their  heights  from  the  reference,  1.50, 
2.21  to  6.25  meters. 

The  total  cubic  mass  was  18,000  cubic  meters;  it  was  paid  for  at 
the  rate  of  70.49  francs  per  cubic  meter,  the  excavated  rock  and 
cement  being  provided  by  the  Government. 


PART  III.— BRIDGES  AND  VIADUCTS. 


Chapter  XXIX. — The  new  Steel  bridge  at  Rouen  on  the 

Seine. 

(263)  The  new  bridge  at  Rouen  was  constructed  to  replace  a sus- 
pension toll  bridge  built  in  1836. 

The  bridge  (Figs.  173-175)  consists  of  steel  arcs  resting  on  ma- 
sonry piers  and  abutments.  It  is  unsymmetric,  a condition  which 
was  imposed  by  the  peculiar  circumstances  of  its  situation.  It  is 
formed  of  three  spans  of  40,  48.80,  and  54.60  meters,  with  rises  of 
2.50,  3.70,  and  4.87  meters,  besides  a straight  portion  of  16.80  me- 
ters span  with  an  intermediate  support  on  columns.  The  complete 
length  of  the  work  is  176.30  meters.  The  width  of  the  bridge  be- 
tween parapets  is  20  meters — 14  for  the  roadway  and  6 for  the  two 
sidewalks.  The  quays  on  the  two  banks  are  not  parallel ; they  are 
at  an  angle  of  4°  5';  the  two  spans  of  the  bridge  are  therefore  slightly 
skew.  The  foundations  were  made  by  means  of  compressed  air, 
except  those  for  the  rear  abutment  on  the  left,  which  was  founded 
on  piles.  The  steel  arcs  are  nine  in  each  span — five  under  the  road- 
way, two  under  the  sidewalks  near  the  edges,  and  two  at  the  sides. 
The  seven  intermediate  arcs  have  plates  0.60  meter  wide  ; the  thick- 
ness of  these  plates  is  0.033  meter  for  the  five  arcs  under  the  road- 
way and  0.022  meter  for  the  two  intermediate  arcs.  The  border  arcs 
have  plates  0.30  meter  wide  and  0.022  meter  thick.  The  heights  of 
the  arches  are  as  follows : 


At  the 
crown. 

At  the 
springing 
lines. 

Span— 

Meters. 

Meters. 

40.00 

0.423 

0.652 

48.80 

0.522 

0.802 

54.60 

0.622 

1.002 

The  arches  alone  are  of  steel.  The  spandrels  and  upper  roadway 
are  of  iron.  The  spandrels  are  formed  of  uprights,  braced  crosswise 
only,  and  not  longitudinally  ; their  spacing  varies  from  2.57  to  2.67 
meters,  according  to  the  span.  The  upper  roadway  is  formed  of 
longitudinal  bearers  resting  on  the  uprights  of  the  spandrels,  and 

745 


746 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


united  by  crossbeams  supporting  brick  arches  0.11  meter  thick,  hav- 
ing a span  varying  from  1.13  to  1.18  meters.  The  arches  under  the 
roadway  are  of  solid  brick ; those  under  the  sidewalks  of  hollow 
brick.  Toward  the  keystone  the  longitudinal  bearers  disappear,  and 


the  cross  girders  rest  directly  upon  the  ai’ches,  which  gives  to  the 
work  an  appearance  of  great  lightness.  Two  expansion  joints  are 
arranged  for  each  bearer.  The  span  on  the  right  is  formed  of  eight 


CIVIL  ENGINEERING,  ETC. 


747 


steel  beams  0.346  meter  high,  with  widths  of  plate  of  0.40  meter  for 
the  intermediate  beams,  and  of  0.25  meter  for  the  end  ones.  These 
beams  are  united  by  iron  ci*oss  girders  supporting  the  arches  of  the 
roadway  and  sidewalks.  The  arches  were  built  on  centers  resting  on 
piles.  The  same  center  served  for  the  three  spans.  It  consisted  of 
nine  trusses  from  2.70  to  2.20  meters  apart. 


per  cubic  meter;  the  masonry  53. 50  francs  per  cubic  meter.  The  prices 
per  kilogram  of  the  metals  were  as  follows : Steel,  0. 57  franc ; 
iron,  0.45  franc;  ornamental  cast  iron,  0.34  franc;  ordinary  cast 
iron,  0.24  franc. 


748 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


The  plans  for  the  bridge  were  prepared  by  M.  Junker,  engineer, 
and  M.  Lavoinne,  chief  engineer.  It  was  erected  under  the  super- 
intendence of  M.  Mengin,  chief  engineer,  and  Cadart,  assistant. 
M.  De  Dartein,  professor  of  architecture  in  the  Polytechnic  School 
and  in  that  of  Roads  and  Bridges,  made  the  architectural  and  deco- 
rative designs  for  the  work. 

Chapter  XXX. — Reconstruction  of  the  roadway  of  the 

SUSPENSION  BRIDGE  AT  TONNAY-CHARENTE — ALTERNATELY 

TWISTED  CABLE. 

(265)  The  road  from  Bordeaux  to  St.  Malo  crosses  the  Charente 
above  the  port  of  Tonnay-Charente,  6 kilometers  above  Rochefort. 
At  this  point  the  mean  width  of  the  river  is  80  meters.  On  the  right 
bank  is  a hill,  on  which  the  town  is  built.  On  the  left  bank  is  an 
extensive  alluvial  plain  nearly  horizontal,  situated  slightly  above 
high -tide. 

The  toll  bridge,  constructed  in  1842,  consisted  of  three  spans,  united 
upon  the  left  bank  with  a masonry  viaduct  passing  over  by  a con- 
tinuous declivity  of  0.05  per  meter,  the  difference  of  level  between 
the  roadway  of  the  bridge  and  the  plain.  Ships,  which  come  up  to 
Charente,  have  a free  space  of  22  meters  above  high  water  under  the 
central  span. 

The  foundations  were  established  on  the  rock  on  the  right  side  and 
upon  piles  for  the  two  piers.  As  to  the  abutment  on  the  left,  and 
the  viaduct  of  approach,  it  was  founded  simply  on  the  natural  soil  by 
means  of  a masonry  platform  resting  on  a layer  of  sand  1 meter 
thick.  Considerable  settling  took  place  during  the  work,  but  after- 
ward a state  of  equilibrium  was  established  and  no  motion  was 
observed  in  the  masonry. 

(266)  In  1883  it  was  decided,  in  consequence  of  the  rupture  of  the 
suspension  bridge  while  it  was  being  tested,  to  reconstruct  it,  under 
conditions  much  better,  both  as  to  the  stability  and  the  preservation 
of  the  work.  (Fig.  176). 

The  total  opening  between  the  two  abutments  is  206  meters,  divided 
into  three  parts ; two  end  spans  of  58  meters,  and  a central  one 
of  90.  The  necessity  of  resting  no  load  upon  the  left  bank  viaduct, 
founded  as  we  have  said  very  lightly,  induced  the  engineer  to  carry 
the  whole  load  on  the  piers  taking  the  points  of  support  on  these 
piers  and  bringing  the  lowest  point  of  the  parabola  on  a level  with 
the  viaduct  so  that  the  traction  of  the  cables  should  be  nearly  hori- 
zontal without  any  vertical  component.  The  three  span  roadway  is 
held  at  each  end: 

First.  From  the  axis  of  the  piers  to  13.65  meters  on  each  side  by 
five  oblique  cables  called  rigid. 

Second.  By  five  cables  with  parabolic  curvature  to  which  the 
suspension  rods  are  attached  carrying  the  roadway.  These  last  cables 


CIVIL  ENGINEERING,  ETC. 


749 


have  only  to  sustain  G2.70  meters  of  the  cable  in  the  central  spans  and 
44.35  meters  at  each  of  the  side  spans.  Their  deflection  is  5 meters  in 


the  central  span,  7.79  meters  for  the  span  on  the  left  hank,  and  7.17 
meters  for  the  span  on  the  right. 

The  piers  supporting  this  structure,  not  having  the  dimensions 


750 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


sufficient  to  form  abutment  piers,  can  be  exposed  only  to  compressive 
stress.  For  this  purpose  the  difference  of  tension,  resulting  from  the 
different  positions  of  the  proof  load,  is  met  by  cables  or  retaining 
guys,  four  on  each  side  per  span,  joining  the  tops  of  the  piers  and 
anchored  at  the  base  of  the  abutments. 

(207)  In  order  that  the  piers  shall  undergo  no  overturning  effort 
there  is  arranged  at  the  top  of  each  an  expansion  truck  rolling 
within  certain  limits  upon  an  iron  plate.  This  truck  carries  the  steel 
pin  0.100  meter  in  diameter  which  serves  to  unite  the  suspension 
cables  and  the  guys.  It  carries  besides  two  pins  0.09  meter  for  the 
oblique  cables. 

The  towers  are  of  iron.  At  their  upper  part  they  are  solidly  united 
by  an  arched  roadway  with  ribbed  plate  iron  flooring  and  a parapet, 
so  that  the  trucks  and  suspension  joints  may  be  easily  inspected. 
The  suspension  rods  are  united  to  the  cable  so  that  they  may  be  taken 
off  and  replaced  easily  without  interrupting  the  traffic. 


Fig.  177.— Method  of  attaching  the 
cables. 


Fig.  17S. — Method  of  attaching  the 
suspension  rods. 


For  this  purpose  the  head  of  each  suspension  rod,  instead  of  being 
carried  above  the  cable  according  to  the  old  custom,  is  suspended 
below  by  five  little  stirrups  (Fig.  178). 

(268)  By  the  aid  of  this  simple  arrangement  the  removal  of  these 
cables  offers  no  difficulty.  When  the  screws  of  all  the  little  stir- 
rups are  taken  away  the  cable  hangs  freely,  subjected  only  to  the 
tension  of  its  own  weight.  It  is  only  required  to  unscrew  the  great 
stirrup,  which  at  each  extremity  holds  the  cable  passing  through 
holes  arranged  for  this  purpose  in  the  cast-iron  back  piece,  where  it 
is  wedged  through  a conical  hole  (Fig.  177).  The  same  series  of 
operations  reversed  allows  the  cable  to  be  replaced. 

The  guys  are  furnished  also  at  their  extremities  with  mild  steel 
stirrups;  this  permits  them  to  be  changed  and  allows  the  tension  to 


CIVIL  ENGINEERING,  ETC.  751 

bo  regulated.  All  the  cables  and  guys  are  attached  to  the  top  of 
the  piers  as  has  been  indicated. 

Each  suspension  cable  is  attached  by  means  of  a back  piece  and 
two  steel  straps  to  a rectangular  bar,  one  end  being  inserted  in  a hole 
made  in  the  masonry  on  one  side,  and  the  other  resting  against  an 
iron  bar  embedded  in  the  pit  walls.  Facilities  for  the  removal  of 
the  cable  are  thus  provided.  As  an  extra  precaution,  there  is  a sec- 
ond anchorage  formed  of  two  bars  embedded  in  the  masonry  and 
united  to  the  first  system  by  rods  with  plates  and  nuts. 

On  account  of  its  situation  the  bridge  is  particularly  exposed  to 
the  wind.  Without  entering  into  the  details  of  its  construction,  we 
may  say  that  the  roadway  was  made  very  rigid,  and  that  wind 
bracing  was  used,  consisting  of  a system  of  diagonal  fiat  bars  placed 
in  the  plane  of  the  upper  crossbeams ; also  by  sets  of  guys  attached 
to  the  crossbeams  and  anchored  on  the  shore. 

(2G9)  The  cable. — All  the  cables  except  the  suspension  rods  are  of 
twisted  wire  arranged  in  concentric  layers  and  twisted  alternately 
in  opposite  directions  (Fig.  179). 


Fig.  179. — >1.  Arnodin’s  alternately  twisted  cable,  one-third  of  the  natural  size. 


Consequently  all  the  wires  in  the  same  cable,  except  the  central 
one,  have  the  same  length,  and  when  the  cable  is  stretched  all  the 
wires  are  equally  elongated.  This  is  a property  which  belongs  only 
to  cables  with  straight  wires,  and  to  those  which  are  alternately 
twisted.  The  tensions  of  the  different  wires  produced  by  the  elon- 
gation of  cables  twisted  in  the  ordinary  way,  as  in  American  cables 
have  very  different  values.  These  cables  manufactured  by  M.  Ar- 
nodin  may  be  called  alternately  twisted  cables. 

The  alternately  twisted  cables  have  a very  much  greater  flexibility, 
which  will  be  easily  understood  when  we  consider  that  the  points  of 
contact  are  fewer,  and  consequently  the  adhesion  much  less.  The 
ratio  of  the  hollow  to  the  full  portions  is  much  greater  than  in  the 
simply  twisted  cable;  it  varies  from  0.15  to  0.30,  according  to  the 
number  of  wires.  Before  the  cable  is  manufactured  the  wires  are 
passed  through  a bath. of  inoxidizable  composition;  then,  as  each 
layer  or  crown  is  added,  the  cable  passes  anew  through  this  bath,  so 
that  all  the  wires  and  all  the  layers  are  covered,  and  the  interior  spaces 
between  tangent  circumferences  are  filled  with  this  composition. 

(270)  The  vertical  suspension  rods  are  the  only  ones  which  have 
parallel  wires,  in  order  not  to  complicate  their  attachment  to  the 
transverse  beams  and  the  parabolic  cables. 

The  old  roadway  weighed  1,354  kilograms  per  running  meter,  and 
would  only  allow  the  passage  of  two  5-ton  carriages  at  a time. 


752 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


The  new  superstructure  weighs  1,368  kilograms  per  running  meter, 
and  will  permit  two  carriages  of  7 tons  to  rest  on  the  same  cross 
beam.  Hence,  without  altering  sensibly  the  weight  of  the  super- 
structure, which  was  a necessary  condition  on  account  of  the  state 
of  the  piers,  they  were  able  to  obtain  a much  greater  strength  and 
stiffness  in  the  new  structure.  . 

(271)  Cost. — Suspension  superstructure,  etc.,  264,976.70  francs  ; 
administration  expenses,  demolition  of  the  old  superstructure, 
masonry,  etc.,  34,826.42  francs;  total,  299,803.12  francs. 

The  reconstruction  of  the  superstructure  was  planned  and  carried 
out  by  M.  Arnodin,  under  the  supervision  of  M.  Potel,  chief  engineer 
and  Caparon,  assistant. 

I am  indebted  to  Mr.  Arnodin  for  information  and  drawings. 
Chapter  XXXI. — The  lifting  bridge  at  La  Villette,  Paris. 


(272)  The  port  of  Villette  consists  of  two  basins  of  unequal  lengths 
(70  and  30  meters),  separated  by  Crirnde  street,  which  has  a daily 
traffic  amounting  to  four  thousand  vehicles.  A channel  60  meters 


Lifting  bridge  at  La  Villette,  Paris. 


Fig.  180.— Elevation. 


mm 

T i 

Am 

long  and  11  meters  wide  connects  these  basins.  This  channel  was 
widened  to  15  meters,  and  a lifting  bridge  (Figs.  180  and  181)  was 
erected  over  it.  This  bridge  weighs  85  tons ; it  is  balanced  by 


CIVIL  ENGINEERING,  ETC. 


753 


four  counterpoises,  one  at  each  corner,  descending  into  a dry  masonry 
pit.  The  visible  portion  of  the  mechanism  consists  only  of  chains 
and  guide  pulleys  with  their  supports,  which  are  decorative  cast-iron 
columns.  The  bridge  being  balanced,  the  only  efforts  to  be  overcome, 
both  in  ascent  and  descent,  are  those  due  to  the  friction  and  rigidity 
of  the  moving  parts,  which  are  estimated  at  about  5,000  kilograms. 
The  moving  mechanism  consists  of  two  cylinders  placed  under  the 
abutments  of  the  bridge,  having  their  piston  heads  permanently  at- 
tached to  the  superstructure.  The  necessary  synchronism  of  motion 
in  the  pistons  is  accomplished  by  a shaft,  with  beveled  wheels  at 
each  extremity,  which  in  turn  drives  two  transverse  shafts  provided 
with  spur  wheels  gearing  into  racks  placed  on  each  upright  post 
(Fig.  182). 


Fig.  181.— Transverse  section. 


In  order  that  the  pressures  under  the  pistons  shall  be  exactly  equal, 
two  conduits  are  placed  in  the  superstructure,  which  communicate 
with  the  interior  of  the  piston  rod,  and  empty,  one  above,  and  the 
other  below  the  piston  (Fig.  183). 

The  lower  surface  of  the  piston  is  double  the  annular  upper  sur- 
face. When  the  pressure  acts  upon  both  faces  the  bridge  rises; 
when  the  pressure  acts  only  on  the  upper  face,  the  lower  being  con- 
nected with  the  exhaust,  the  bridge  descends;  hence  the  whole  valve 
work  is  reduced  to  a three-way  cock  (Fig.  184),  connecting  the  bot- 
tom of  the  cylinder  with  the  admission  or  the  exhaust. 

H.  Ex.  410 — vol  ill 48 


754 


UNIVERSAL  EXPOSITION  OP  1889  AT  PARIS. 


Lifting  bridge  at  La  Villette,  Paris. 


Fig.  183.— Details  of  a press  and 
the  superstructure. 


CIVIL  ENGINEERING,  ETC. 


755 


To  facilitate  repairs,  and  to  make  up  for  a certain  amount  of  play, 
tlie  cylinders  are  suspended  on  trunnions,  so  as  to  oscillate  length- 
wise of  the  bridge. 

The  pistons  being  hinged  to  the  superstructure  the  latter  might 
move  about  the  trunnions  were  it  not  maintained  in  its  upright  po- 
sition by  guides.  These  guides  consist  of  four  tenons  projecting 
from  the  ends  of  the  beams  into  channels  made  for  that  purpose  in 
the  iron  columns  (Fig.  182).  These  tenons  are  united  two  and  two 
at  each  end  of  the  bridge  by  a very  rigid  piece  to  which  the  lifting 
chains  are  attached. 


Fio.  184.— Three-way  cock  for  the  lifting  bridge  at  La  Villette. 

(273)  The  roadway. — The  stringers  and  crossbeams  carry  a 
wrought-iron  paneling  upon  which  is  laid  a mixture  of  sawdust  and 
wooden  splinters  mixed  with  hot  tar,  and  upon  this  mass,  properly 
curved,  a wooden  pavement  0.10  meter  high  is  placed’(Fig.  183). 

The  intermediate  mixture  weighs  about  1.000  kilograms  and  costs, 
when  placed,  100  francs  per  cubic  meter. 

Resistance  and  elasticity. — A trial  panel  with  an  intermediate  thick- 


756 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


ness  of  only  0.015  meter  resisted  satisfactorily  a blow  of  8 tons  fall- 
ing from  a height  of  0.30  meter,  there  being  no  permanent  change  of 
form  or  rupture  of  the  filling. 

The  bridge  is  frequently  operated  by  a child.  Its  complete  lift  is 
4.  GO  meters,  and  the  time  of  lifting  50  or  GO  seconds. 

The  cost  was  140,000  francs,  not  including  the  masonry. 

The  bridge  was  built  by  M.  L.  Le  Cliatelier,  engineer,  under  the 
direction  of  M.  Humblot,  chief  engineer. 

I am  indebted  to  M.  Chateliers  article  for  the  drawings  and  in- 
formation contained  in  this  chapter.* 

A working  model  of  this  bridge  was  shown  in  the  pavilion  of  the 
city  of  Paris. 

Chapter  XXXII. — The  Garabit  Viaduct. 

(274)  History. — M.  Boyer,  the  engineer  in  charge  of  the  prelimi- 
nary survey  for  locating  the  railroad  between  Marvejols  and  Neus- 
sargues,  found  that  he  could  avoid  constructing  the  road  on  the  side 
of  a very  broken  range  of  hills,  and  thus  save  a distance  of  20  kilom- 
eters, by  crossing  the  Truyfere  at  Garabit  cut,  where  the  valley  nar- 
rows, being  bordered  on  each  side  by  elevated  planes. 

The  adoption  of  this  line  necessitated  the  construction  of  an  im- 
mense viaduct  120  meters  above  the  river. 

Under  these  circumstances  M.  Boyer  applied  to  M.  Eiffel  asking 
him  to  prepare  the  preliminary  plans  and  estimates  for  such  a via- 
duct. similar  to  the  one  built  across  the  Douro,  at  Oporto,  eighteen 
months  before. 

The  reply  of  M.  Eiffel  showed  that  such  an  exceptional  structure 
could  be  erected,  which  would  be  entirely  satisfactory  both  as  to  its 
stability  and  its  cost ; and  that  M.  Boyer  could  thus  adopt  the  new 
line  on  the  plateau,  cross  the  valley  by  a viaduct  122  meters  above 
the  stream,  and  still  make  a saving  of  three  millions  of  francs  over 
the  road  as  originally  projected,  and  at  the  same  time  have  a much 
better  working  line. 

Under  these  circumstances  the  project  for  the  viaduct  furnished 
by  M.  Eiffel  was  approved,  and  he  was  authorized  to  construct  it 
under  the  supervision  of  MM.  Bauby  and  Lefranc,  chief  engineers, 
and  MM.  Boyer  and  Lamotte,  assistant  engineers. 

(275)  Description. — The  Garabit  viaduct  is  built  over  the  River 

Truyfere  at  Garabit,  for  the  railroad  from  Marvejols  to  Neussargues. 
It  crosses  a deep  valley  and  passes  over  an  undulating  plateau  (Fig. 
185).  It  carries  a single  line  of  rails.  The  iron  portion  has  a total 
length  of  448.30  meters,  which  is  prolonged  at  its  extremeties  by 
masonry  viaducts  forming  abutments.  The  rails  are  at  a reference 
of  835.50  meters— that  is  to  say,  122.20  meters  above  the  deepest  part 
of  the  valley.  


* Annales  des  Ponts  et  Chaussees,  Sixth  Series,  Vol.  11. 


758 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


The  iron  viaduct  (Fig.  185)  is  composed  of  straight  girders  resting 
upon  masonry  abutments  at  the  ends,  and  upon  intermediate  wrought- 
iron  piers  on  eacli  side  of  the  valley,  and  upon  struts  standing  upon 
an  iron  arch  of  165  meters  span.  We  shall  now  give  a description  of 
these  parts: 

(276)  The  horizontal  superstructure  is  not  continuous  for  its  whole 
length,  it  is  interrupted  at  the  two  struts  upon  the  arch,  and  con- 
sist, properly  speaking,  of  three  consecutive  portions. 

First.  That  on  the  Marvejols  side,  which  extends  from  the  Mar- 
vejols  abutment  to  the  first  strut  on  the  arch. 

Second.  The  central  portion,  which  is  included  between  the  two 
struts. 

Third.  The  Neussargues  portion,  which  extends  from  the  second 
strut  of  the  arch  to  the  Neussargues  abutment. 

The  portion  on  the  Marvejols  side  consists  of  five  spans,  as  follows: 
Two  end  spans  of  51.80  meters  divided  into  fourteen  panels  of  3.70 
meters  each,  giving  a total  length  of  103.60  meters;  three  interme- 
diate spans  of  55.50  meters,  giving  166.50  meters  ; finally  a flush  panel 
resting  on  the  abutment  having  a width  of  0.24  meter;  total,  270.34 
meters. 

The  central  portion  consists  of  three  equal  spans  of  24.64  meters, 
divided  into  six  panels  of  4.106  meters,  and  giving  total  length  of 
73.92  meters.  Finally  the  girder  on  the  Neussargues  side  has  two 
equal  spans  of  51.80  meters  forming  fourteen  panels  of  3.70  meters, 
giving  a total  length  of  103.60  meters,  to  which  must  be  added  the 
full  panel  upon  the  Neussargues  abutment,  0.24  meter,  making  a 
total  of  103.84  meters. 

The  two  end  portions  are  fixed  upon  the  great  iron  piers  which  form 
the  abutments  of  the  arch.  They  are  able  to  expand  freely  on  each 
side;  and  to  allow  for  the  motion  produced  by  the  variations  of  tem- 
perature there  exists  upon  the  abutments  a play  of  0.25  meter  for 
the  Marvejols  portion,  and  0.10  meter  for  the  Neussargues  portion 
between  its  ends  and  the  stone  guard,  and  a play  of  0.10  meter 
between  its  extremity  and  the  central  portion  on  the  struts. 

The  central  girder  is  fixed  at  the  two  middle  points,  and  rests 
freely  on  the  struts. 

(277)  The  roadway  (Fig.  189)  is  placed  1.66  meters  below  the  flange 
of  the  longitudinal  girder,  which  thus  forms  a parapet  of  great 
stiffness. 

The  girders  are  5.16  meters  high  and  5 meters  apart.  The  upper 
and  lower  members  have  the  form  of  a f,  and  are  united  by  a simple 
lattice  and  by  vertical  struts. 

Each  of  the  members  consists  of  a vertical  web  600x15  and  two 
horizontal  angle  irons  and  a uniform  flange  500  X 10.  Sup- 

plementary plates  are  added  wherever  the  calculations  require  it,  as 


CIVIL  ENGINEERING,  ETC. 


759 


shown  on.  the  drawings.  The  lattice  bars  are  T -shaped,  and  consist 
of  a flange  and  two  angle  irons,  and,  in  the  central  girder,  simply  of 
a web  and  two  angle  irons.  The  uprights  have  a double  T section 


formed  by  two  angle  irons 


80X80 

10 


and  a web  8 millimeters  thick. 


Above  the  supports,  these  uprights  are  replaced  by  a strong  flush 
panel  to  guarantee  the  transmission  of  the  efforts  coming  from  the 
lattice  bars.  (The  dimensions  are  usually  given  in  millimeters). 

The  transverse  girders  are  attached  to  the  longitudinal  girders  at 
the  uprights  of  the  panels.  They  have  the  form  of  a double  T con- 

70  X 70 

sisting  of  a web  700x8  and  four  angle  irons,  — . This  trans- 
verse girder  is  supported  in  the  middle  by  two  struts,  each  formed  of 

two  angle  irons  c<  put  together.  These  struts  are  attached  to 

the  feet  of  the  uprights.  They  are  united  at  their  lower  parts  by  a 

80  x 80 

tie  rod  formed  of  two  angle  irons  — ^ . Finally,  two  bars  simi- 

lar to  the  struts,  which  they  cross  at  their  middle  point,  are  attached 
to  the  uprights  below  the  transverse  girder  and  to  the  center  of  the 
tie  rod,  thus  forming,  with  the  uprights,  the  transverse  girder,  the 
tie  rods  and  the  struts,  a very  stiff  bracing  (Figs.  189,  B and  C). 

The  cross-girders  are  united  to  each  other  by  five  rows  of  longi- 
tudinal bearers.  They  consist,  in  the  lateral  girders,  of  a web 

90  x 90 

550x7  and  four  angle  irons  — , but  in  the  central  girder,  where 


the  span  of  the  cross-girders  is  greater,  the  angle  irons  are  — ^ , 

the  web  being  the  same. 

These  bearers  carry  the  metallic  flooring,  which  is  composed  of 
iron  plates  0.240X  120  and  sufficiently  strong  to  support  the  weight 
of  a locomotive  in  case  of  derailment;  also,  the  principal  girders  form 
a parapet  strong  enough  to  prevent  the  fall  of  the  derailed  engine. 
Besides  this  advantage,  the  flooring,  which  is  almost  continuous, 
presents  a second,  viz,  that  of  forming  an  almost  perfect  wind- 
bracing to  the  girder  at  the  level  of  the  roadway. 

A lower  wind-bracing,  consisting  of  a single  lattice  in  which  each 

bar  is  formed  of  two  angle  irons  , gives  the  two  girders  the 

greatest  solidity  to  resist  horizontal  displacement.  The  girders  rest 
upon  hinged  supports,  some  movable  and  others  fixed.  Each  sup- 
port consists  of  an  upper  part  of  wrought-iron  which  is  fixed  under 
the  flanges  of  the  girders  and  which  carries  a slot  in  which  is  lodged 
a wedge  to  regulate  the  level  of  the  superstructure.  This  wedge  rests 
on  a lower  piece  of  cast-iron  having  a slot  so  arranged  as  to  gear  with 
that  of  the  upper  piece  and  prevent  lateral  motion.  The  lower 


760 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS, 


Garabit  Viaduct.  Central  Portion. 


Fig.  186.  Elevation. 


Fig.  A.  Sections  k I,  in  n,  o p,  q r.  s t,  u v, 


Fig.  187.  Wind  bracing  of  the  extrados  between 
the  bottom  of  the  arch  and  the  first  strut. 


Fig.  188.  Wind  bracing  on  the  iutrados  between 
the  two  struts. 


CIVIL  ENGINEERING,  ETC. 


761 


piece  has  different  forms  according  as  the  support  is  fixed  or  mova- 
ble. In  the  case  of  the  movable  support,  this  piece  has  a less  height 
and  rests  on  cast-iron  rollers.  These  latter  have  the  form  of  seg- 
ments which  may  be  increased  in  number  by  bringing  them  nearer 
together.  They  rest  upon  a cast-iron  plate.  The  use  of  hinged  sup- 
ports has  the  advantage  that  the  vertical  reaction  of  the  supports 
always  passes  through  its  axis,  a condition  of  absolute  necessity  for 
iron  piers  of  great  height. 

(278)  The  arcli. — The  great  arch  has  a chord  1G5  meters  long;  its 
rise  is  51.853  meters,  and  its  height  at  the  crown  10  meters.  It 
consists  of  two  lattice-work  principals  placed  symmetrically  with 
respect  to  the  middle  plane  of  the  arch,  but  in  oblique  planes  thereto. 
The  planes  of  these  principals,  which  are  20  meters  apart  at  the 
origin,  approach  each  other  toward  the  crown,  where  the  distance 
of  separation  is  only  0.28  meters,  measured  at  the  extrados;  hence 
the  inward  slope  per  meter  is  0.11008  with  respect  to  the  vertical. 
This  arrangement  gives  great  stability  to  the  arch,  enabling  it  to 
resist  the  most  violent  winds.  The  principal  ribs  are  cruciform  in 
section;  the  mean  fiber  is  a parabola.  It  has  a great  height  at  the 
crown,  and  terminates  in  a point  at  each  springing  line  where  it 
rests  on  the  abutments  by  a knee  joint.  This  form  obviates  the  use 
of  spandrels,  the  stresses  of  which  are  difficult  to  ascertain  by  cal- 
culation, and  may  vary  considerably  by  expansions  or  the  displace- 
ment of  the  rolling  load,  while  their  unusual  dimensions  would 
require  an  enormous  amount  of  iron. 

The  rigidity  which  this  form  gives  to  the  principals  enables  them 
to  resist,  independently  of  all  the  accessory  pieces,  changes  of  form 
resulting  from  the  unequal  distribution  of  the  loads ; and  it  has, 
besides,  the  advantage  of  avoiding  all  uncertainty  as  to  the  point 
in  which  the  resultant  of  the  forces  strikes  the  abutment,  since  it 
can  only  be  the  point  of  contact  of  the  pivot  with  the  cushion  stone, 
which  remains  the  same  whatever  may  be  the  alteration  in  form  of 
the  arch. 

The  intrados  and  extrados  members  of  each  arched  girder  are 
connected  by  a lattice  and  by  vertical  struts,  except  in  the  panel  next 
the  springing  lines,  which  is  flush  (PL  IX). 

These  members,  with  their  open  interior  faces  (Fig.  18G),  consist 
of  two  webs  0.60  meters  high,  strengthened  by  two  angle  irons,  and 
riveted  to  the  flanges  by  four  angle  irons.  The  flanges  themselves 
are  formed  of  a variable  number  of  plates  0.65  meter  wide. 

The  verticals  and  trellis  work  are  of  angle  irons  and  flat  bars 
(Fig.  A). 

The  principals  are  united  by  horizontal  braces,  each  formed  of  four 
angle  irons  (70  millimeters)  united  by  a plate  iron  trellis,  except  at 
the  base,  where  there  is  a full  web  properly  strengthened.  Again, 
in  the  plane  of  each  of  these  braces  is  a vertical  wind  bracing,  each 


762 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


bar  having  the  section  u'  v',  Fig.  C,  united  by  a trellis  of  flat  bars, 
except  at  the  lower  panel  which  is  flush.  Finally  the  connection  of 
the  two  arcs  is  completed,  both  at  the  intrados  and  the  extrados,  by 
bracing  (Figs.  187  and  188),  each  brace  consisting  of  a square  box 
trellis  formed  of  four  angle  irons  with  a double  lattice  of  iron  plate 
bars  on  their  faces  (PI.  IX). 

(279)  The  iron  piers  are  in  the  form  of  the  frustrum  of  a pyramid, 
their  edges  or  standards  being  girders  properly  braced  (Fig.  18G). 

In  the  Douro  bridge,  built  by  the  same  constructor,  the  standards 
were  box  girders.  In  this  case,  for  the  faces  of  piers  at  right  angles 


Fig.  189.  Side  elevation.  Fife.  C.  Cross  sections  Fig.  B.  End  elevation, 

o'  p',  s'  t,  u'  v,  q r,  x'  y’. 


to  the  roadway,  which  resist  the  force  of  the  wind,  the  standards 
have  a |J  shape,  in  which  horizontal  and  diagonal  braces  are  in- 
serted, having  the  form  of  box  trellis  girders  (PI.  IX). 

This  arrangement  allows  easy  access  and  is  capable  of  resisting 
compression  as  well  as  tension. 

(280)  Principal  dimensions. — The  piers  (Fig.  189)  are  of  the  fol- 
lowing heights,  counting  from  the  viaduct  on  the  Marvejols  side, 
measured  from  the  masonry  foundation,  viz,  24.51.  36.46,  51.20,  60.73, 
and  60.73  meters. 

The  batter  in  the  piers  1,  2,  3 is  0.08272  per  meter ; in  Xos.  4 and 


t 


Paris  Exposition  of  1889— Vol.  3.  Civil  Enoineerino,  etc.  — PLATE  IX. 


GARABIT  VIADUCT. 


THE  LOWER  PORTION  OF  THE  ARCH  WITH  ITS  SUPPORTING  PIER. 


CIVIL  ENGINEERING,  ETC.  763 

5 it  is  0.11088  in  the  plane  of  the  great  face.  The  transverse  batters 
are  0.0386  and  0.0388,  respectively. 

The  piers  are  divided  into  panels  10  meters  high,  measured  along 
the  axis  of  the  standard.  Each  pier  terminates  in  a coping,  which 
receives  the  supports  of  the  superstructure.  The  piers,  as  well  as 
the  ai’ch,  are  anchored  in  the  masonry,  as  shown  in  Fig.  186. 

In  each  pier  a spiral  staircase  is  placed,  so  that  every  part  may  be 
inspected. 

(281)  Stresses. — The  plans  for  the  masonry  work  were  wholly  pre- 
pared by  the  Government  engineers. 

The  calculation  of  the  stresses  in  the  ironwork  were  made  by  M. 
Eilfel,  and  verified  by  M.  Boyer  by  other  methods  and  found  correct. 

The  sti*ess  was  to  be  limited  to  6 kilograms  per  square  millimeter 
under  the  combined  action  of  the  loads  and  the  wind. 

The  surcharge  was  to  consist  of  a locomotive  weighing  75  tons 
drawing  a train  of  cars  weighing  15  tons  each. 

The  effect  of  the  wind  was  supposed  to  be  150  kilograms  per  square 
meter  while  the  trains  were  running,  and  270  while  they  were  not, 
at  which  time  the  traffic  would  be  suspended. 

In  the  calculation,  the  wind  was  supposed  to  act  uniformly  on  the 
side  towards  it,  and  to  act  solely  on  the  trellis  bars  on  the  opposite  side. 
To  this  there  was  added  its  effect  on  the  train,  which,  as  the  train  is 
partly  protected  by  the  upper  members  of  the  girder,  was  estimated 
as  acting  on  1.6  square  meters  per  running  meter.  This  figure,  1.6, 
was  adopted  by  M.  Nordling  in  calculation  of  the  great  viaducts  on  the 
Orleans  Railroad  system,  which  were  also  constructed  by  M.  Eiffel. 

The  effects  produced  by  the  load  and  wind  are  such  that  the  mem- 
bers of  the  arch  may  be  regarded  as  bearing  2 kilograms  per  square 
millimeter  under  the  ordinary  load,  2 kilograms  per  square  millime- 
ter from  the  effect  of  the  surcharge  alone,  and  2 kilograms  per  square 
millimeter  from  the  effect  of  the  wind,  so  that  the  section  of  the 
members  is  one-lialf  greater  than  it  would  be  if  the  effect  of  the 
wind  had  been  neglected. 

The  influence  of  temperature  is  very  slight  when  added  to  the 
loads.  The  maximum  pressure  at  the  crown  of  the  arch  under  a 
variation  of  30  degrees  is  only  0.63  kilogram  per  square  millimeter. 

(282)  Erection  of  the  ironwork. — At  the  commencement  of  the 
work  the  country  around  the  viaduct  was  a complete  desert.  It  was 
necessary  to  begin  by  building  offices  and  lodgings  for  the  overseer, 
and  for  the  engineers  when  they  visited  the  grounds,  storehouses 
for  the  materials,  repair  shops,  lodgings  for  the  workmen,  stables 
for  the  horses,  and  also  a school  for  the  children  of  the  workmen. 
On  account  of  the  difficulty  of  access  M.  Eiffel  erected  a service 
bridge  on  a level  with  the  foundation  of  the  chief  pier,  33  meters 
above  the  stream.  The  head  of  this  bridge  was  united  with  the  na- 
tional highway  by  a road  built  on  the  side  of  the  ravine.  On  this 


704 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


roacl  a storehouse  was  erected  for  the  iron,  with  traveling  cranes  for 
unloading  the  wagons  which  brought  it  from  Neussargues  station. 

The  platform  of  the  bridge  supported  two  lines  of  railroad,  by 
which  the  materials  were  brought.  All  the  foundations  were  laid 
on  very  resisting  schist. 

The  masonry  constructions  presented  no  difficulty.  While  the  iron 

Gar abit  Viaduct.  Erection  op  the  iron  arch. 


a 

‘5b 

a> 

PQ 

I 

s 


2 

£ 


piers  were  in  process  of  erection  two  portions  of  the  superstructure 
of  the  bridge  were  set  up  on  the  right  and  left  banks.  When  all 
was  ready  these  portions  were  pushed  forward  so  as  to  overhang  the 
central  piers  by  a distance  of  22.20  meters  over  the  arched  space. 
The  end  of  each  portion  of  the  superstructure  was  made  fast  by 
twenty-eight  steel  cables  to  the  masonry  abutments  of  the  accessory 


CIVIL  ENGINEERING,  ETC. 


765 


viaducts,  and  then  preparations  were  made  for  raising  tlie  arcli  by 
building  two  principal  scaffoldings  in  front  of  the  two  foundations 
of  the  abutment  piers  up  as  high  as  the  pivots. 

The  upper  parts  of  the  scaffoldings  were  curved  so  as  to  form  a 
center  for  the  members  of  the  intrados  of  panels  1 and  2,  which  were 
arched;  then  the  outer  extremity  of  this  arch  was  held  by  twenty 
steel  cables  made  fast  to  the  overhanging  superstructure  (Fig.  190), 


and  then  they  proceeded  to  erect  the  overhanging  arch  by  attaching 
new  pieces  to  those  already  riveted  in  place. 

When  the  overhanging  portion  erected  balanced  that  of  the  lower 
part,  whicli  occurred  at  the  fifth  panel,  a new  set  of  cables  uniting 
vertical  strut  5 with  the  upper  superstructure  was  put  in,  and  the 
work  was  continued  to  strut  9 (Fig.  191). 

Again,  twenty-four  cables  starting  from  struts  8 and  9 were  made 


766 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


fast  to  the  superstructure,  and  the  work  so  progressed  until  the 
crown  was  reached  (see  Plate  X).  The  erection  went  on  simulta- 
neously on  each  side. 

(283)  Methods  of  raising  the  pieces. — The  pieces  were  raised  in  two 
different  ways;  the  heavy  pieces  were  brought  by  cars  on  the  service 
bridge  exactly  under  their  intended  position.  Rolling  shears,  placed 
on  that  portion  of  the  arch  already  built,  supported  powerful  winches 
which  raised  these  heavy  pieces  (Fig.  190). 

For  the  light  pieces,  there  were  erected  above  the  central  piers 
two  wooden  stagings  10  meters  high,  which  held  a steel-wire  cable 
tramway  spanning  the  distance  of  177  meters  between  the  piers.  The 
cable  carried  two  cages,  one  for  each  side  (Fig.  191). 

The  cables  were  made  with  great  care  with  a hemp  core  surrounded 
with  eight  strands,  each  of  nineteen  wires  of  0.0024  meter  in  diameter. 
It  withstood  a tensile  stress  of  125  kilograms  per  square  millimeter, 
and  each  wire  could  be  bent  double  eight  times  before  breaking. 

The  diameter  of  the  cable  was  0.043  meter,  and  the  weight,  6.5 
kilograms  per  running  meter.  The  rupture  of  one  cable  would  have 
required  an  effort  of  85  tons,  and  during  the  erection  no  cable  had 
to  bear  a load  exceeding  15  tons. 

(284)  Proofs. — The  proof  load  was  made  up  of  a train  formed  by 
a locomotive  weighing  75  tons,  drawing  cars  of  15  tons.  The  de- 
flection observed  in  spans  loaded  separately  was  from  0.016  to  0.019 
meter. 

The  arch  loaded  along  its  whole  length  by  a train  of  405  tons  had 
a deflection  of  0.008  meter.  The  same  train  occupying,  successively, 
half  the  length  of  the  arch  gave  a deflection  of  0.010  meter. 

In  the  proofs  for  rolling  load,  the  maximum  deflection  in  the  spans 
was  from  0.015  to  0.018  meter,  and  that  of  the  arch  at  the  crown 
0.012  meter.  The  horizontal  displacement  of  the  superstructure 
during  the  passage  of  a train  was  from  6 to  8 millimeters.  After 
each  proof  the  parts  of  the  structure  resumed  their  exact  primitive 
position. 

(285)  General  information. 

Weight  of  the  metal  employed kilograms. . 3, 326, 414 

Amount  of  masonry cubic  meters. . 20,409 

Cost: 

For  the  ironwork francs. . 2,350,000 

For  the  masonry  do..  . 850,000 

Total  do. ...  3, 200, 000 

The  works  were  begun  in  January,  1880,  and  terminated  in  Novem- 
ber, 1884. 

M.  Eiffel  was  assisted  by  MM.  Emile  Nouguier,  Maurice  Koechlin, 
M.  Compagnon,  and  M.  J.  B.  Gobert. 

I am  indebted  to  the  Eiffel  Co.  for  valuable  information,  plans, 
and  drawings  of  this  most  interesting  work. 


V 


Paris  Exposition  or  1889  -Vol.  3. 


Civil  Engineering,  etc.  — Plate  X 


GARABIT  VIADUCT  DURING  THE  PROCESS  OF  ERECTION. 


CIVIL  ENGINEERING,  ETC. 
Chapter  XXXIII. — Gour-Noir  Viaduct. 


767 


(286)  The  Gour-Noir  Viaduct  is  situated  on  the  railroad  from 
Limoges  to  Brive  nearUzerche,  4 kilometers  beyond  this  last  locality, 
where  it  crosses  the  river  Vez&re  at  an  angle  of  about  50  degrees. 

This  river  winds  through  a deep  and  very  precipitous  valley;  sud- 
den freshets  are  frequent,  and  the  direction  of  the  current  varies  with 
the  freshets.  For  this  reason  it  was  preferred  to  cross  the  river  with 
an  arch  of  great  span,  and  as  there  was  excellent  building  material 
in  the  vicinity  this  arch  was  projected  with  a span  of  GO  meters. 
The  work  (Fig.  192)  is  built  for  two  tracks  and  has  a width  of  8 
meters  between  the  parapets.  Its  total  length  is  108.46  meters. 
The  radius  of  the  intrados  is  36  meters,  that  of  the  extrados  44- 
meters;  the  rise  is  1G.  10  meters.  The  thickness  of  the  arch  at  the 
keystone  is  1.70  meters,  at  the  springing  lines  4.20  meters.  The 
spandrels  are  open  with  six  small  arches  with  a span  of  4.30  meters 
each.  Idle  wing  walls  are  flush  in  elevation,  but  their  filling  is  hol- 
lowed out  in  the  interior  by  hidden  arches  of  G meters  span.  Com- 
munication between  these  arches  is  made  by  openings  1.50  and  1.55 
meters  in  diameter  and  with  the  outside  by  a manhole  0.80  meter 
in  diameter.  Between  the  spandrels  and  the  wing  walls  are  the 
buttresses,  2.85  meters  wide  at  the  top,  which  allows  the  establish- 
ment of  refuges  rendered  necessary  by  the  length  of  the  work.  In 
the  part  between  the  buttresses  there  is  a parapet  of  open-work 
limestone,  the  only  part  of  the  work  not  of  granite.  To  aug- 
ment the  stability  different  batters  were  given  to  different  parts  of 
the  construction.  The  mean  pressure  at  the  keystone  is  16.60  kilo- 
grams per  square  centimeter,  and  the  maximum  pressure  is  33.20 
kilograms.  On  the  ground  under  the  foundation  the  pressure  does 
not  exceed  9.80  kilograms. 

The  centers  are  made  by  seven  trusses,  1.56  meters  apart,  each 
formed  of  a lattice  beam  4.40  meters  high,  on  which  rests  a system 
of  pieces  in  the  direction  of  the  radii  and  having  a fan-shaped  ap- 
pearance. The  rigidity  of  this  fan  is  insured  by  two  courses  of  bri- 
dle pieces.  Each  truss  rests  upon  the  lower  support  by  means  of 
interposed  sand  boxes.  The  lower  supports,  that  is  to  say,  all  the 
parts  below  the  sand  boxes,  are  eleven  in  number,  each  one  consist- 
ing of  nine  piles. 

From  the  nature  of  the  river  bed  it  was  impossible  to  shoe  the 
piles  and  drive  them  in  the  ordinary  manner ; the  piles  were  placed, 
and  held  by  cement,  in  holes,  some  of  which  were  bored  out,  and 
others  hollowed  out  by  stonecutters  using  steel  drills  under  the 
shelter  of  cofferdams. 

Cost. — The  cost  of  the  viaduct  was  235,202  francs.  The  projects 
were  made  and  the  works  executed  under  the  direction  of  M.  Doniol, 
inspector-general.  The  engineers  were  M.  Daigremont,  chief  engi- 
neer, and  M.  Draux,  assistant. 


768 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


CIVIL  ENGINEERING,  ETC.  76(4 

Chapter  XXXIV. — Viaduct  over  the  river  Tardes. 


(287)  The  viaduct  on  the  railway  from  Montlugon  to  Eygurande 
crosses  tlie  Tardes  near  Evaux,  and  has  an  iron  superstructure  rest- 
ing on  masonry  supports.  It  consists  of  three  spans,  the  middle  one 
100.05  meters,  the  two  others  are  each  GO. 45  meters  (Figs.  103  and  104). 

The  piers  at  the  top  are  4.50  by  8 meters.  These  dimensions  in- 
crease from  the  top  to  the  bottom.  The  pier  on  the  left  side  is  50.05 
meters  high,  that  on  the  right*  48.02  meters.  The  abutments  are 
14.50  by  0.40  meters,  with  a hollow  interior. 

The  roadway  consists  of  two  great  girders  8.30  meters  high,  with 
double  lattice  faces  distant  5.50  meters  from  center  to  center.  The 
track  is  placed  above.  The  tops  of  the  girders  are  0.80  meter  wide 
and  form  a sidewalk  above  the  latter.  The  distance  between  the 
parapets  is  G.30  meters.  The  two  girders  are  united  by  two  courses 
of  horizontal  wind  braces,  one  below  and  the  other  above,  and  by 
vertical  struts.  The  rails  are  supported  by  wooden  stringers  resting 
upon  stringers  of  iron  united  to  the  cross  girders  spaced  2.55  meters. 
The  roadway  is  curved  with  a radius  of  250  meters  at  the  entrance 
and  exit  of  the  superstructure.  A parabolic  arc  was  intercalated 
between  each  curve  and  the  right  line  portion  of  the  middle  structure. 
The  rails  are  91.33  meters  above  the  valley. 

The  piers  are  founded  on  compact  granite  rock  and  the  abutments 
upon  hard  tuffa. 

(288)  Cost. — The  total  expense  was  1,400,000  francs,  that  is,  107 
francs  per  superficial  meter  of  the  vertical  projection.  The  pressure 
upon  the  masonry  piers,  including  their  own  weight  and  that  of  the 
superstructure,  with  the  proof  loads,  was  7 kilograms  per  square 
centimeter.  It  reached  the  figure  of  9 kilograms  by  taking  account 
of  the  moment  of  the  wind  against  the  roadway  during  the  passage 
of  a train  extending  along  the  whole  length. 

The  greatest  stresses  to  which  the  iron  is  subjected  under  the  dif- 
ferent proof  loads  and  the  effect  of  the  wind  are  the  following:  G kilo- 
grams per  square  millimeter  for  the  members  of  the  girders,  the 
cross-beams,  and  the  sleepers  under  the  rails ; 5 kilograms  per  square 
millimeter  for  the  lattice,  thehorizontal  wind  braces,  and  the  vertical 
struts;  and  4 kilograms  per  square  millimeter  for  the  rivets. 

Besides,  the  members  of  the  lattice  girders  as  well  as  the  wind 
braces  were  strengthened,  so  that  during  the  operation  of  launching 
the  stress  did  not  exceed  at  any  point  8 kilograms  per  square  milli- 
meter. 

The  work  was  planned  and  carried  out  under  the  direction  of  M. 
Daigremont,  chief  engineer,  and  N.  Guillaume,  assistant. 

The  contractor  was  M.  Eiffel. 

H.  Ex.  410— vol  ill 49 


770 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS, 


KIos.  19.)  and  194. — Elevation  and  plan  of  the  Tardes  viaduct. 


CIVIL  ENGINEERING,  ETC. 


771 


Chapter  XXXV. — Consolidation  of  the  side  slopes  at 

La  Plante. 

(■-289)  The  railroad  from  Hopital-du-Grobois  to  Lods  passes  be- 
hind the  town  of  Ornans  in  a deep  cut  through  caving  gravel. 
The  cut  was  almost  completely  opened,  when  on  account  of  the  win- 
ter rains  of  1882-’S3  they  perceived  a rising  of  the  roadway  amount- 
ing to  2 meters  in  height,  combined  with  a general  advancement  of 
the  upper  slope  without  any  change  in  its  form.  At  the  same  time 
the  bridge  which  crossed  the  cut  (Fig.  195)  was  exposed  to  such  a 
thrust  that  its  keystone  rose  0.21  meter  and  the  upper  abutment 
advanced  0.G4  meter,  notwithstanding  a strong  bracing  rapidly 
made  to  stay  it  against  the  lower  abutment.  Finally,  openings  in 
the  hill  at  a distance  of  90  meters  from  the  crest  of  the  cutting  were 
observed,  covering  a space  of  about  3.30  hectars  of  ground.  A num- 
ber of  borings  showed  that  the  mass  of  gravel  in  which  the  cutting 
was  opened  rested  upon  stratified  marl,  but  at  the  separation  there 
was  a thin  layer  of  plastic  clay  very  wet  by  the  abundant  exudation. 
The  cutting  having  taken  away  the  thrust  of  the  hill,  the  latter 
slipped  bodily  upon  the  soapy  layer  of  compressed  clay,  raising  the 
soil  of  the  roadway  which  was  stopped  by  the  opposite  slope.  To 
prevent  this  slipping  the  following  means  were  employed:  It  was 
thought  best  to  first  divide  the  mass  in  motion  into  sections  by  the 
aid  of  fixed  pillars.  These  piliars  were  made  by  great  dry  stone 
spurs  of  2 meters  thick,  having  a length  proportioned  to  the  im- 
portance of  the  mass  in  motion.  These  spurs  rested  on  the  side  of 
the  cutting  upon  great  masses  of  masonry  5 meters  thick  and 
3 meters  wide,  themselves  buttressed  against  the  lower  wall  of  the 
cut  by  means  of  a reversed  arch  placed  under  the  roadway.  Al- 
though these  constructions  presented  a great  resistance  against  the 
motion,  it  was  also  advantageous  to  drain  the  water  of  exudation  be- 
forehand, and  to  thus  dry  the  mass  immediately  in  front  of  the  cut. 
These  points  being  settled,  it  was  only  necessary  to  oppose  the  mo- 
tions of  the  intermediate  masses  placed  between  two  consecutive 
spurs  and  partially  drained  by  them.  For  that  purpose  a revetment 
was  built  formed  of  arches  of  7-metA-  span,  the  axis  having  an 
inclination  of  one-third  to  the  vertical.  These  arches  were  1 meter 
thick  at  the  crown.  They  were  supported  by  a rear  wall  having 
a uniform  thickness  of  3 meters.  Finally,  to  catch  all  the  exuda- 
tions which  escaped  from  the  spurs,  these  arches  were  covered  with 
dry  stone  and  all  the  water  was  collected  in  a drain  which  went  from 
one  end  of  the  walls  to  the  other.  This  last  work  had  such  dimen- 
sions that  it  could  be  inspected  easily,  and  the  satisfactory  condition 
of  the  drainage  could  be  told  at  each  instant,  by  means  of  manholes. 
On  account  of  the  longitudinal  undulations  of  the  stratified  marls 
on  which  the  wall  is  founded,  the  rear  wall  of  this  last,  which  con- 


Flo,  1115.  —Side  slopes  at  La  Plante  after  the  completion  of  the  work  of  eo 


773 


CIVIL  ENGINEERING,  ETC. 

tains  the  culvert,  is  more  or  less  imbedded  in  this  subjacent  layer; 
hut  at  no  point  did  the  plane  of  slipping  pass  above  the  top  of  the 
arch  in  order  to  avoid  crushing  this  work.  It  is  understood  that  in 
the  portions  built  into  the  stratified  marl  the  thickness  of  the  wall 
foundation  is  reduced  as  much  as  possible  to  allow  the  construction 
of  the  culvert.  The  drainage  system  worked  perfectly,  the  amount 
of  water  caught  amounted  sometimes  to  350  liters  per  minute,  and 
went  down  to  10  liters  in  the  season  of  great  droughts. 

These  different  works  were  not  carried  out  without  great  difficulty, 
and  from  the  first  great  masses  were  obliged  to  be  moved  to  erect  in 
the  middle  of  the  slope  a banquette  of  2 meters. 

Since  March,  1885,  when  the  works  wei'e  finished,  the  motion  has 
entirely  ceased. 

The  length  of  the  cut  consolidated  is  416.77  meters;  the  surface  in 
motion  was  about  3.30  hectares,  and  its  mass  attained  150,000  cubic 
meters.  The  total  cost  of  consolidation  amounted  to  391,770.46 
francs,  which  made  the  cost  per  running  meter  of  the  consolidation, 
940  francs. 

The  work  was  planned  and  carried  out  under  the  direction  of 
Inspector-General  Cabarrus  by  M.  Chatel,  chief  engineer,  and  Bar- 
rand.  assistant. 

Chapter  XXXVI.— Tunnel  through  Cabkes  Pass  on  the  Rail- 
road from  Crest  to  Aspres  les  Veynes. 

(•290)  The  prolongation  of  the  Livron  and  Crest  Railroad  to  Aspres 
les  Veynes  contains,  at  Cabres  Pass,  a tunnel  3,770  meters  long.  This 
important  work  is  laid  out  in  a right  line  3,306.14  meters  from  the 
crest  head;  then  it  is  prolonged  with  a curve  of  800  meters  radius 
for  393.44  meters,  and  terminates  in  a right  line  70.42  meters  long. 
It  rises  in  an  incline  of  0.020  for  14  meters,  of  0.015  for  472  meters, 
and  of  0.009  for  2,358.77  meters  to  attain  its  summit  at  the  altitude 
of  884.086  meters,  whence  it  descends  toward  the  station  at  Baume 
by  a declivity  of  0.003  for  a distance  of  925.23  meters.  The  Cabres 
Tunnel  has  been  planned  with  two  tracks,  although  the  line  has 
only  one  ; this  arrangement  was  made  tv  facilitate  ventilation,  which 
a single-track  section  would  not  have  been  enough  to  guarantee ; it 
allows  trains  to  cross,  and  diminishes  the  danger  of  a derailment  in 
the  middle  of  such  a long  tunnel. 

The  tunnel  is  to  be  completely  lined  with  masonry,  varying  from 
0.50  to  0.80  meter,  according  to  the  nature  of  the  strata.  A flooring 
will  extend  through  the  whole  length,  and  a central  drain  to  collect 
the  water.  Refuge  niches  are  established  at  distances  of  50  meters 
in  each  wall,  and  a storage  chamber  is  placed  also  at  the  middle  of 
the  tunnel. 

The  most  important  point  of  beginning  is  the  crest  head ; on 
this  side  two  55  horse  power  steam  engines  are  placed,  which  drive 


774  UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 

•the  air  compressors  to  work  the  rock  drills,  the  ventilators,  and  a 
gramme  dynamo  furnishing  t lie  electric  lighting,  for  a part  of  the 
gallery  and  the  works  adjacent  to  the  tunnel,  during  the  night.  The 
work  of  the  drills  produced  a mean  advancement  of  from  5 to  7 me- 
ters per  day.  Sometimes  this  advancement  was  stopped  on  account 
of  explosive  gas  which  was  given  off  in  great  quantities  and  rendered 


Fio.  197. — Center  used  in  Cnbres  I’ass  Tunnel. 

an  exceptional  ventilation  indispensable.  In  view  of  preventing  the 
danger,  ventilation  by  suction  was  substituted  for  forced  ventilation. 
Precautions  were  taken  by  the  use  of  safety  lamps,  the  explosion  of 
the  mines  by  electricity,  the  periodical  examination  of  the  air,  etc. 
The  suction  produced  by  a conduit  0.50  meter  in  diameter  and  2,000 


Fig.  196. — Half  sections  of  the  C'abres  Pass  Tunnel. 


775 


CIVIL  ENGINEERING,  ETC. 

meters  long  having  ceased  to  he  sufficient,  a vertical  shaft  was  sunk 
1,920  meters  from  the  crest  head.  A natural  current  then  established 
itself  and  carried  away  the  explosive  gas.  If  necessary,  an  exhaust- 
ing fan  might  be  placed  at  the  upper  orifice  to  aid  the  natural  draft. 
This  tunnel  was  driven  in  the  layers  of  marl  belonging  to  the  Ox- 
fordian strata,  which  swells  and  rises  by  contact  with  air,  and 
requires  a strong  revetment.  The  contractors  used  for  centers  iron 
arcs,  which  had  the  advantage  (Fig.  197)  of  occupying  very  small, 
space. 

(291)  Cost. — The  cost  is  estimated  as  follows: 


Francs. 

Driving  the  tunnel 3, 770, 000 

Masonry 2,639,000 


Total 6,409,000 


That  is,  1,700  francs  per  running  meter. 

The  works  are  executed  by  M.  Pesselon,  engineer,  under  the  direc- 
tion of  M.  Berthet,  chief  engineer. 

Chapter  XXXVII. — Cubzac  Bridge  over  the  Dordogne. 

(292)  The  railroad  from  Cavignac  to  Bordeaux  crosses  the  Dor- 
dogne valley  at  913  meters  below  the  bridge  constructed  at  Cubzac 
for  the  national  roadway  No.  10.  The  free  height  under  the  road- 
way was  determined  by  the  condition  of  putting  no  obstacle  to  the 
free  passage  of  vessels  going  up  to  Libourne.  This  condition,  to- 
gether with  the  configuration  of  the  ground,  required  the  construc- 
tion of  great  works  extending  over  a length  of  more  than  2 kilo- 
meters, consisting  of : 

First.  An  iron  viaduct  on  the  right  bank  with  a slope  of  0.008  for 
a length  of  294.58  meters.  (Fig.  198  and  199). 

Second.  An  iron  bridge  of  5G1.60  meters  over  the  Dordogne,  in  a 
straight  line  with  the  first. 

Third.  Upon  the  left  bank,  which  was  flat  and  low,  at  2 meters  be- 
low the  level  of  the  highest  waters,  an  iron  viaduct  599.23  meters 
long,  continued  by  a masonry  viaduct  579.23  meters  long.  These  two 
last  works  are  on  a curve  1,500  meters  radius,  and  have  a slope  of 
one  centimeter  per  meter.  The  viaduct  of  the  right  bank  rests  on 
masonry  piers.  It  is  formed  of  six  spans  of  44.98  meters  each,  with 
an  upper  roadway.  The  principal  beams  are  diagonally  braced  with 
vertical  uprights.  The  panels  are3.4G  meters  span. 

The  Dordogne  bridge  rests  on  iron  piers  and  includes  eight  spans, 
the  two  end  ones  being  of  GO,  and  the  six  intermediate  73.60  meters 
long.  Its  principal  beams  have  a double  lattice  web  of  3.20  meters 
opening  without  uprights.  The  roadway  is  26  meters  above  low  wa- 
ter. The  iron  viaduct  on  the  left  side  rests  on  masonry  piers  like 
those  on  the  opposite  bank.  Its  general  aspect  is  the  same,  but  on 


17  6 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


account  of  the  curvature,  its  thirteen  spans  of  44.98  meters  are  inde- 
pendent. 

The  masonry  viaduct  consists  of  40  arches  of  12-meters  span.  It 


is  g 
3 J§ 

tc 


to 

a 5 


o 

£ M 


a 

Ph 

s * 

0 

fc 


has  a width  of  8.40  meters  at  the  springing  lines,  with  an  exterior 
hatter  of  0.03  meter  per  meter  carried  to  0.05  meter  for  the  but- 
tresses. 


CIVIL  ENGINEERING,  ETC. 


777 


(‘293)  The  Dordogne  bridge  rests  on  two  abutment  piers  and  on 
seven  river  piers.  The  calcareous  marl  rock  on  which  its  founda- 
tions rest  in  perfect  security  is  17.50  meters  below  low  water.  Com- 
pressed air  was  used  in  making  the  foundations ; the  caissons  of  the 


Fig.  199.— Elevation  of  a pier  of 
the  viaduct  of  approach  left 
bank). 


Fig.  200.— Elevation  of  an  abutment  of  theCubzac  bridge 
over  the  river  Dodogne. 


abutments  are  rectangular  with  rounded  angles.  They  were  17.00 
meters  long  by  9.80  meters  wide.  (Fig.  200). 

The  height  of  the  working  chamber  was  2 meters ; its  plate-iron 
ceiling,  6 millimeters  thick,  was  sustained  by  lattice  beams  0.97  me- 


778 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


ter  high,  united  to  the  caisson  walls  by  vertical  gussets  terminated 
by  struts,  thus  consolidating  the  iron  plates.  Heavy  angle-iron 
beams,  placed  around  the  periphery,  which  were  in  turn  strength- 
ened by  outside  plates  22  by  2 centimeters,  stiffened  the  cutting  edge. 
The  sinking  was  accomplished  by  gradually  lowering  the  air  pres- 
sure when  the  pits  had  attained  the  required  depth. 


All  the  piers  rested  on  limestone  except  the  fourth  (the  deepest), 
which  descended  29.20  meters  below  high-water  level  into  a layer  of 
compact  gravel.  Under  the  pressure  of  three  atmospheres,  attained 
in  the  caisson  in  summer,  the  work  became  extremely  difficult  and 
even  dangerous  ; the  lateral  pressures  were  so  intense  that  the  pier. 


CIVIL  ENGINEERING,  ETC. 


779 


notwithstanding  its  weight,  remained  in  equilibrium  and  could  not 
descend  more  than  3 or  4 centimeters,  even  by  suddenly  lowering 
the  air  pressure.  It  was  not  therefore  possible  to  go  down  4 meters 
further  to  the  rock  under  the  gravel  bank. 

The  iron  pier  supports  (Fig.  201)  are  anchored  in  the  masonry  by 
means  of  eight  iron  tie  rods  0.10  meter  in  diameter,  and  four  of  0.05 
meters,  bolted  under  a flooring  of  iron  beams.  The  iron  framework 
consists  of  six  standards  united  by  struts  and  braces  and  surmounted 
by  a coping  on  which  are  placed  the  supports  of  the  superstructure. 
The  bridge  is  anchored  upon  the  central  pier  and  provided  on  the 
other  piers  with  steel  expansion  trucks.  The  principal  girders  are 
braced  at  their  upper  parts  by  lattice  girders  0.58  meter  in  height ; 
at  their  lower  part  by  plate  iron  girders  carrying  the  stringers. 

The  horizontal  wind  bracing  is  obtained,  below,  by  the  plate-iron 
flooring  riveted  to  the  stringers  and  the  cross  girders;  above,  by  lat- 
tice bracing.  • 

(204)  The  launching  was  effected  by  means  of  rollers  moved  by 
levers,  on  each  of  the  piers;  but,  on  account  of  the  great  length  of 
the  bridge,  this  operation  was  divided  into  two  parts,  forming  two 
fields  of  erection,  one  on  the  right  bank  and  the  other  on  the  left. 
The  same  staging  served  for  both  halves  of  the  roadway.  The 
erection  took  place  as  the  launching  went  forward,  and  the  junction 
of  the  two  halves  was  made  on  the  central  pier. 

The  weight  of  each  half  of  the  superstructure  was  1,700  tons,  and 
its  length  280  meters.  The  peculiarities  worthy  of  notice  in  this 
operation  are : 

The  application  of  supporting  rollers  with  double  oscillation,  di- 
viding equally  the  load  on  two  rollers  placed  under  the  two  webs  of 
the  double  beams. 

The  launching  levers  were  moved  by  means  of  a steam  engine  set 
up  on  the  superstructure  for  the  last  spans. 

Buffers,  riveted  upon  the  heads  of  the  beams  on  the  piers,  were 
used  to  prevent  the  fall  of  the  superstructure  in  launching,  on  ac- 
count of  lateral  displacement  which  might  be  occasioned  by  the 
winds  or  any  other  cause. 

The  first  two  spans  were  launched  by  hand  power.  The  launch- 
ing of  the  second  required  120  men;  the  third  and  fourth  would 
have  required  at  least  from  250  to  300  men.  With  the  employment 
of  such  a great  number  of  hands,  separated  from  each  other  by  a 
distance  of  75  meters,  the  opei’ation  could  not  have  been  made  with 
perfect  uniformity,  and  the  total  effort  would  have  been  far  from 
corresponding  to  the  sum  of  the  partial  efforts.  To  obviate  this  dif- 
ficulty the  contractors  substituted  for  the  hand  lovers  a system  of 
traction  by  a steam  engine  arranged  so  as  to  drive  simultaneously 
all  the  levers  requisite  for  the  operation. 


780 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


(295)  Apparatus  with  a universal  joint,  for  launching  by  steam. — 
This  system  consists  of  an  iron  frame  resting  at  its  central  part  on 
a steel  axle.*  This  axle  allows  the  frame  to  oscillate,  like  a balance 
beam,  lengthwise  of  the  bridge.  The  frame  itself  carries  at  each  end 
another  frame,  oscillating  transversely  and  carrying  independent 
rollers. 

The  lower  axle  of  the  principal  frame  allows  the  system  to  tip 
longitudinally,  and  thus  guarantees  the  constant  contact  of  the  two 
rollers  on  the  same  end  with  the  bottom  of  the  bridge. 

The  transverse  axles  allow  the  transverse  frame  to  tip  in  the  case 
of  a difference  of  level  between  the  two  members  of  the  same  gir- 
der, and  thus  equalize  upon  the  four  rollers  the  load  supported  by 
the  apparatus. 

The  rollers  are  0. 50  meter  in  diameter.  Each  apparatus  is  calcu- 
lated to  support  240  tons,  that  is,  60  on  each  roller. 

A rachet  wheel  is  keyed  to  the  shaft  of  each  outer  roller,  and  the 
rollers  are  moved  by  long  levers  turning  freely  on  the  shafts  and 
carrying  pawls.  These  levers  are  united  transversely  by  braces,  and 
longitudinally  by  jointed  connecting  rods  to  which  bars  and  chains 
are  attached.  Each  chain  passes  over  a chain  pulley  at  the  over- 
hanging end  of  the  bridge,  and  thence  to  the  transverse  shaft  driven 
by  the  engine,  whence  it  is  wound  on  a drum  placed  in  the  rear. 

A friction  coupling  is  placed  on  the  motor  shaft,  to  interrupt  the 
forward  motion  of  the  levers  and  to  regulate  their  return,  which  is 
done  automatically  by  the  action  of  counterpoises. 

Each  of  these  counterpoises  is  formed  of  two  weights  suspended  a 
certain  distance  from  each  other,  so  that  both  act  at  the  beginning  of 
the  returning  movement.;  then,  as  the  levers  approach  the  vertical 
position,  the  resistance  diminishing,  the  first  counterpoise  rests  upon 
a platform,  leaving  the  second  to  act  alone  until  in  its  turn  it  ceases 
to  act;  the  levers  then  having  passed  the  vertical  position,  their  own 
weight  suffices  to  bring  them  back.  A cord  around  a second  drum, 
keyed  to  the  same  shaft  as  the  first,  holds  a counterpoise,  and  thus 
tightens  the  chain  after  each  oscillation  of  the  levers. 

This  system  of  launching  by  steam  was  perfectly  satisfactory, 
giving  a regular  and  gentle  forward  movement  to  a mass  weighing 
1,700  tons,  at  the  rate  of  6 inches  per  hour. 

Cost. — The  total  cost  of  these  works  amounted  to  9,040,000  francs. 

The  plans  were  made  and  the  work  carried  out  by  MM.  Prompt 
and  Girard,  engineers. 

The  ironwork  was  constructed  and  the  superstructure  of  the  bridge 
launched  by  MM.  Lebrun,  Dayde'  and  Pi  lid. 


* A horizontal  bar  rounded  on  the  top. 


CIVIL  EXGDTEERTXG,  ETC. 

Chapter  XXVIII.— The  Crueize  Viaduct. 


781 


(200)  The  Crueize  Viaduct  is  situated  on  the  line  from  Marvejols 
and  Neussargues  at  the  point  where  it  crosses  the  river  Crueize,  9' 
kilometers  from  Marvejols  station..  It  consists  of  six  arches  of  25 
meters  span  and  has  a total  length  of  218.80  meters.  The  maximum 
height  of  the  rails  above  the  lowest  point  of  the  valley  is  63.30 
meters.  It  is  founded  on  gneiss.  It  has  two  tracks,  and  its  width 
is  8 meters  between  the  parapets.  At  the  right  of  the  buttresses  of 
the  piers  this  width  is  10  meters.  The  arches  of  the  intrados  consist 
of  two  quarters  of  circles  having,  respectively,  12.915  and  12.085 
meters  radii.  This  arrangement  has  for  its  object  to  give  a slight 
slope,  at  the  same  time  maintaining  the  level  of  the  springing  lines 
of  the  two  adjacent  arc-lies.  This  mode  of  obtaining  the  slope  has 
the  advantage  of  bringing  the  resultant  of  the  pressures  toward  the 
center  of  the  pier. 

The  arches  are  1.30  meters  in  thickness  at  the  crown  and  2.60 
meters  at  the  joints  of  rupture.  The  spandrils  are  lightened  by  three 
longitudinal  archways  of  1.20  meters  span.  The  piers  have  on  all 
sides  a batter  decreasing  gradually  from  the  base  to  the  top.  This 
equalizes  the  pressure  upon  the  different  courses,  and  leaves  the 
edges  continuous. 

At  the  same  time,  to  facilitate  the  laying  of  the  edge  stones,  a 
series  of  right  lines  5 meters  long,  forming  an  inscribed  polygon  in 
the  theoretical  curve,  is  substituted  for  the  curve  itself,  the  curve 
corresponding  to  a constant  pressure  upon  the  different  courses. 
This  substitution  is  not  observable  in  the  work  itself. 

The  buttresses  are  placed  against  the  piers  and  rise  just  to  the  top. 
They  are  2 meters  wide  at  the  springing  and  project  at  the  spandrel 
1 meter  at  the  level  of  the  plinth.  The  maximum  depth  of  the 
foundation  is  10  meters  and  the  mean  depth  0.50  meters.  The  mean 
pressures  per  square  centimeter  of  the  different  sections  of  the  piers 
are  from  8.20  to  10  kilograms.  . The  use  of  cut  stone  is  limited  to 
the  coping. 

The  centers  were  sustained  by  a double  row  of  rails  passing 
through  the  masonry  piers.  The  first  support,  carrying  the  foot  of 
the  rafters,  consisted  of  the  two  rails  ; the  second,  placed  4 meters 
below,  was  formed  of  a single  rail  upon  which  rested,  by  an  inter- 
vening plate,  the  braces  sustaining  the  principal  rafters.  The  cen- 
ters for  raising  were  placed  on  the  upper  flooring  of  the  service 
bridge  used  in  erecting  the  piers. 

The  total  cost  was  1,289,893.43  francs,  whch  gives  per  square 
meter  of  vertical  projection  in  sight,  the  foundations  not  included, 
105.80  francs. 

The  engineers  were  M.  Bauby,  engineer  in  chief,  and  M.  Boyer, 

assistant. 


782  UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 

Chapter  XXXIX. — Construction  of  the  Castelet,  the  An- 
toinette. AND  THE  LaVEUR  BRIDGES. 

(297)  These  bridges  have  single  arches  of  41.20,  50,  and  Cl.  50  meters 
of  span,  respectively  ; the  first  erected  over  the  Aridge  at  Castelet,  the 
second  over  the  Agout  near  Vielmur.  the  third  at  Laveur. 

The  adoption  of  a great  arch,  authorized  for  the  three  bridges  by 
the  incompressibility  of  the  foundation,  was  justified  at  Castelet  (Fig. 
202)  by  the  inclination  of  the  line  to  the  river  and  the  violence  of 
the  rapids  between  the  rocks,  in  a bed  encumbered  with  blocks  and 
with  an  indefinite  depth. 

At  Vielmur,  50  meters,  by  the  depth  of  the  river  foundation,  8 
meters,  whifh  made  it  economical  to  build  a great  arch,  founded 
directly  on  the  rock  (Fig.  203). 

Finally  at  Laveur,  Cl. 50  meters,  where  the  foundations  were  facil- 
itated by  the  vicinity  of  a fine  bridge  of  the  eighteenth  century  (Fig. 
204). 


Fig.  202. — Elevation  of  the  Castelet  bridge. 


The  parapets,  spandrels,  and  head  bands  have  a batter  of  one- 
thirtieth  for  Castelet  bridge  and  one  twenty-fifth  for  the  others. 
This  has  the  advantage  of  decreasing  the  stress  on  the  joints  of 
rupture  and  of  offering  greater  transverse  resistance. 

In  the  spandrel  of  the  great  arch  are  smaller  full-centered  arches, 
of  4.50  meters  span  for  the  Laveur,  and  yf  4 meters  for  the  others. 
This  arrangement,  pleasing  in  appearance  when  the  openings  are 
properly  chosen,  has  succeeded  perfectly,  notwithstanding  the  theo- 
retical objection  arising  from  the  danger  of  distributing  the  loads 
in  isolated  zones,  and  the  practical  objection  of  the  tendency  to  fis- 
sures produced  near  the  springing  lines. 

At  Castelet  and  Antoinette  the  open  viaducts  continue  to  the  ex- 
treme abutments;  at  Laveur  they  rest  against  two  strong  pilasters, 
which  cast  heavy  shadows  and  stand  out  prominently  from  the 
neighboring  portions  of  the  work.  This  separation  has  been  accen- 
tuated by  lowering  the  level  of  the  parapet  above  the  8-meter 
arches,  and  stopping  the  architrave  and  coping  of  the  great  arch  at 
the  pilasters. 


Fxo.  204.— Elevation  of  the  Laveur  bridge. 


^nnrtionnnrimnnnniiiinnniinmnmir.TTinnmir.mifL^r^Jimaii: 


784 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


The  extreme  abutments  are  reduced  by  containing  hollow  wells. 
The  principal  dimensions  of  the  great  arches  are  as  follows: 


Castelet. 

Antoinette. 

Laveur. 

Meters. 

Meters. 

Meters. 

Span 

41.203 

50 

61.50 

14 

15.90 

27  50 

Kudins  of  the  intrados  above  natural  ground 

*22.20 

+31 

*31.20 

Thickness  of  keystone 

1.25 

1.50 

1.65 

2. 283 

2.25 

2.81 

Width: 

Between  the  parapets 

5. 65 

4.50 

4. 50 

0. 276 

4.936 

4.80 

7.016 

0.048 

At  the  foundation 

7.209 

6.93 

7.000 

Ratio  between  the  solid  and  hollow  portions  above  ground 

2.98 

2. 18 

1.95 

Cu.  meters. 

Cu.  meters. 

Cu.  meters., 

Masonry 

1,547.28 

2,403 

6,618.67 

Francs. 

Francs. 

Francs. 

Total  cost 

207,000 

224,000 

485,000 

♦On  130°  35'  15."  t On  99°  42' 54 { On  148°  6' 54". 


(298)  Centers — Bolsters  and  Sheathing. — A sheathing  .025  meter 
thick,  on  which  is  drawn  the  position  of  all  the  voussoirs,  is  nailed 
upon  the  bolsters  10  by  14,  spaced  from  the  key  to  the  springing 
line,  from  25  to  50  centimeters  for  the  Castelet;  from  30  to  45  centi- 
meters for  the  Antoinette,  and  from  21  to  45  centimeters  for  the  La- 
veur  bridge. 

Trusses. — Each  center  consists  of  five  trusses,  the  end  ones  being 
slightly  heavier;  each  truss  consists  of  two  stories  resting  one  on  the 
other  by  means  of  nine  files  of  sand  boxes. 

The  back  pieces  are  triple  in  the  Castelet  (Fig.  205),  double  in  the 
Antoinette  (Fig.  206),  and  single  in  the  Laveur  bridge  ^Fig.  207). 
They  are  supported  by  radial  struts  (except  in  the  Antoinette  bridge, 
where  the  river  supports  could  not  be  numerous,  the  alternate  struts 
are  radial,  and  the  intermediate  ones  are  replaced  by  two)  equally 
inclined  to  the  soffit,  forming  a fan-shaped  frame. 

At  the  Castelet  and  Antoinette  bridges  the  fan  (back  pieces,  struts, 
and  the  beam)  rest  directly  on  the  sand  boxes.  At  the  Laveur  bridge, 
on  account  of  the  height,  another  story  has  been  introduced,  consist- 
ing of  vertical  king-posts  and  diagonal-struts,  forming  a series  of 
triangles  whose  vertices  support  the  sticks  of  the  fan. 

(299)  Portion  below  the  sand  boxes. — At  Castelet  (Fig.  205)  the 
upper  portion  is  supported  by  two  double  rafters  inclined  to  the  hori- 
zon by  the  angles  43°,  19°,  and  0°  formed  of  pieces  held  by  straps, 
and  also  by  an  iron  tie  rod.  The  lower  rafters  rest  freely  on  sheets 
of  lead  laid  upon  oak  sleepers  built  into  a masonry  apron. 


CIVIL  ENGINEERING,  ETC. 


785 


H.  Ex.  410 — vol  hi 


50 


.—Center  for  the  Antoinette  bridge.  Elevation  of  a truss. 


Fio.  307.— Center  for  the  bridge;  elevation  of  a truss. 


Laveur  bridge.  Method  op  erecting  the  great  arches. 


788 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


At  Laveur  (Fig.  207)  the  center  rests  on  nine  supports,  three  of 
which  are  double,  united  by  bridle  pieces  forming  seven  files  of  piles, 
two  of  which  serve  as  wave  breakers  and  wind  braces. 

At  Antoinette  (Fig.  20G)  there  are  only  four  supports,  for,  both 
of  the  centers  resting  on  piles,  the  rocky  bottom  would  not  permit 
of  their  being  driven  in  the  usual  way.  Holes  from  1.50  to  2 meters 
in  depth  were  made  in  the  bottom,  slightly  exceeding  the  diameter 
of  the  pile.  The  j>ile  was  cut  off  fiat  and  protected  by  sheet  iron 
against  crushing.  The  holes  were  cleared  by  divers,  the  piles 
lowered  and  held  by  cement,  and  when  necessary  by  wooden  wedges. 

This  system,  which  was  necessary  on  account  of  the  nature  of  the 
bottom,  was  much  more  expensive  than  ordinary  piling,  but  it  was 
justified  by  the  very  slight  settlement  observed  in  the  arch. 

(300)  Construction  of  the  arch — Castelet. — The  arch  was  constructed 
of  two  rings  (Fig.  207  A).  The  thickness  of  the  first  ring  was,  from 
GO  to  40  degrees  (maximum),  1 meter;  from  40  to  20  degrees  (mean), 
0.75  meter;  from  20  degrees  to  the  keystone  (minimum),  0.50  meter. 
Upon  the  heads  only  a single  row  of  voussoirs  was  placed.  The 
first  ring  was  divided  into  six  portions  by  wooden  frames  of  two 

Laveur  Bridge. — Supports  for  tiie  voussoirs  of  the  great  arch  during  erection. 


kinds  (Figs.  208  and  209),  thus  forming  six  great  monolith  vous- 
soirs, the  joints  of  which  were  not  keyed  until  the  ring  had  been 
completed. 

The  keyed  joints  were  firmly  calked  with  powdered  mortar.  The 
second  ring  was  made  in  four  portions,  and  there  were  for  the  two 
rings  eight  keyings. 

The  arch  was  constructed  in  forty-two  days  of  effective  work. 
The  settlements  were,  on  the  center,  53  millimeters ; on  removing 
the  center,  sixty  days  after  the  second  ring  had  been  keyed,  2.02 
millimeters. 

(301)  For  the  Laveur  bridge  (Fig.  207  A).— The  first  ring  was 
divided  into  fourteen  portions  or  monoliths  ; the  second  into  six,  and 
the  third  into  four,  having  in  all  twenty-three  keyings.  The  arch 
was  constructed  in  eighty-two  days  of  effective  work.  The  settle- 


Fig.  208.—  Support  for  the  first  ring. 


Fig.  209. — Support  for  the  second  and  third  rings. 


789 


CIVIL  ENGINEERING,  ETC. 

merits  on  the  center  were,  on  the  downstream  head  16.75  millime- 
ters, on  the  upstream  head  20.07  millimeters,  and  after  striking  the 
center,  one  hundred  and  thirty  days  from  the  time  the  third  ring 
was  keyed,  0.62  millimeter. 

(302)  For  the  Antoinette  bridge. — In  the  first  ring  there  were 
twelve  monoliths  ; in  the  second  eight,  and  in  the  third  four  ; twenty- 
three  keyings  for  the  three  rings. 

The  arch  was  constructed  in  forty-four  and  one-half  days  of  effect- 
ive work.  The  settlements  were,  on  the  center  0.13  meter,  after 
striking  the  center,  a few  days  after  keying  the  third  ring,  0.6  milli- 
meter. 

I am  indebted  to  M.  Sdjournde’s  article  (Annales  des  Ponts  et 
Cliaussdes,  sixth  series,  vol.  12)  for  the  drawing  of  the  centers,  fig- 
ures 205-209,  and  information  respecting  the  erection  of  the  three 

bridges. 

Chapter  XL. — The  Ceret  Bridge. 

(303)  The  Cdret  bridge  is  situated  near  a city  of  the  same  name 
on  the  Tech.  It  consists  of  a great  arch  of  45  meters  span  connect- 
ing two  viaducts.  (Fig.  210). 

The  adoption  of  a great  arch,  made  possible  by  the  solid  ground 
on  the  banks,  was  justified  by  the  necessity  of  avoiding  the  difficult 
and  expensive  foundations  in  the  bed  of  a deep  river  exposed  to 
heavy  freshets. 

The  spandrels  of  the  great  arch  are  hollow,  consisting  of  a viaduct 
of  full  centered  arches  of  3 meters  span,  carried  along  to  two  strong 
pilasters  which  form  prominent  features  of  the  bridge.  They  are 
still  further  marked  by  having  a stone  parapet  above  the  great  arch, 
while  that  above  and  beyond  the  pilasters  is  of  cast  iron. 

The  spandrels  and  head  band  of  the  arch  have  a batter  of  -fa. 
The  arch  and  pilasters  rest  on  a projecting  base  capped  with  cut 
stone. 

The  width  of  the  bridge  between  the  parapets  is  4.62  meters,  and 
the  thickness  of  the  great  arch  at  the  crown  1.40  meters. 

The  head  band  is  of  hewn  stones  of  large  dimensions;  the  thick- 
ness of  the  voussoirs  of  the  arch  is  about  0.42  meter. 

The  stones  of  the  head  band  and  those  of  the  soffit  are  in  rustic 
work,  projecting  0.10  meter  from  the  spandrel.  The  head  bands  of 
the  little  arches  are  roughly  dressed  and  flush  with  the  spandrel 
face. 

The  soffit  is  entirely  of  knotted  ashlar,  of  the  same  width  as  the 
voussoirs  of  the  head  band,  i.  e.,  from  0.60  to  0.90  meter  in  depth 
and  0. 60  meter  long.  This  is  one  of  the  characteristics  of  the  arch. 

There  is  a hydraulic  mortar  capping  0.10  meter  thick  over  the 
extrados,  which  is  also  covered  with  one  of  asphalt,  with  gargoyles 
for  drainage. 


790 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


The  filling  consists  of  a layer  of  sand  0.10  meter  thick  covered 
with  gravel. 

The  plinth,  0.40  meter  thick,  projecting  0.45  meter  from  the  face 
of  the  spandrels,  is  sustained  by  a series  of  modillions  which  requires 
an  appreciable  reduction  in  the  width  of  the  work  under  the  plinth. 

Similarly  the  thickness  of  the  parapet  has  been  reduced  to  a mini- 
mum 0.20  meter  above  the  grand  arch. 

At  intervals,  pilasters  reenforce  the  parapet.  The  stone  is  gi’anite; 
the  greatest  pressure  is,  at  the  keystone,  27  kilograms  per  square 
centimeter.  On  the  foundation  it  is  14.20  kilograms. 

(304)  Centers.  — The  center  of  the  great  arch  consisted  of  four 
trusses  1.35  meters  apart,  formed  of  a fixed  portion  below  the  sand 
boxes,  and  a movable  one  above  them.  The  fixed  portion  consisted 
of  seven  uprights  supporting  the  sill,  on  which  the  boxes  rested,  and 
braced  together  with  bridle  pieces  lengthwise  and  crosswise.  Three 
of  these  uprights  rested  on  framework  supported  by  piles  driven  into 
the  bed  of  the  river.  The  pressures  of  the  three  others  were  borne 
by  shores  set  at  45  degrees  with  the  same  support. 

The  movable  portion  consisted  of  a series  of  back  pieces  resting 
on  the  uprights  placed  at  the  right  of  the  sand  boxes.  Struts  like 
the  sticks  of  a fan  resisted  the  flexure  of  the  back  pieces;  a hori- 
zontal sill  united  the  feet  of  all  the  uprights  and  7’ested  on  the  sand 
boxes.  The  bolsters  were  on  the  back  pieces  and  a sheathing  0.025 
meter  thick  covered  them. 

The  fourth  back  piece  from  the  keystone  placed  below  the  general 
level  of  the  sand  boxes  was  supported  by  a secondary  movable  truss 
resting  on  two  sand  boxes  corresponding  to  the  angle  u7°  30'  from 
the  point  where  the  voussoirs  began  to  rest  on  the  center. 

The  sand  boxes  rested  on  the  sill  by  means  of  stringers.  These 
boxes  were  protected  from  humidity  by  means  of  a pine  box  filled 
with  plaster,  the  upper  layer  of  which  had  been  set. 

The  uprights  of  the  movable  truss  were  bolted  to  the  back  pieces 
by  means  of  iron  gussets  0.003  meter  thick. 

The  center  contained  362  cubic  meters  of  wood;  the  iron  weighed 
5,482  kilograms.  The  cost  was  41,635  francs. 

The  great  arch  was  built  in  its  entire  thickness  up  to  the  angle  67 
degrees  from  the  keystone. 

The  first  nine  courses  which  did  not  rest  on  the  center,  were  built 
with  a templet,  or  form,  upon  which  the  position  of  each  course  was 
marked. 

Above  the  angle  of  60  degrees  the  arch  was  erected  in  double 
rings,  each  in  four  blocks.  The  lowest  block  rested  on  three  courses, 
having  their  joints  filled  with  sheets  of  lead  0.02  meter  thick  and 
having  a space  of  0.10  meter  between  the  edges  of  the  sheets  and 
those  of  the  stones. 

The  upper  block  was  supported  by  joists  uniting  the  triangular 
frames  bolted  upon  the  back  pieces. 


CIVIL  ENGINEERING,  ETC. 


791 


The  four  blocks  were  built  simultaneously.  The  key  block  was 
loaded  to  22  degrees  as  soon  as  the  block  starting  from  GO  degrees 
had  attained  45  degrees. 


They  keyed  the  joints  at  GO  degrees,  taking  out  as  much  as  pos- 
sible of  the  lead.  The  empty  joints  were  filled  with  cement  mortar 


792 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


nearly  dry,  and  driven  in  with  mallets;  the  thickness,  on  account  of 
the  pressure,  being  reduced  from  0.02  to  0.01  meter. 

The  second  ring  was  also  constructed  in  four  blocks  limited  by  the 
same  angles  as  the  first. 

The  center  was  struck  two  months  after  the  second  ring  had  been 
keyed. 

There  was  no  apparent  motion  of  the  arch. 

Cost. — The  cost  was  712,775.49  francs. 

The  plans  were  made  by  M.  Velzey,  under  the  direction  of  M.  Tastre, 
chief  engineer. 

Chapter  XLI. — The  crossing  of  the  Garonne  at  Marmande. — 
The  use  of  masonry  caissons. 

(305)  The  railroad  from  Marmande  to  Casteljaloux  crosses  the 
frequently  submerged  plain  of  the  Garonne,  for  a length  of  4,500 
meters,  which  was  covered  in  the  flood  of  June,  1875,  to  a depth  of 
from  2 to  4.50  meters.  The  plan  (Fig.  211)  shows  the  principal  bed 


Fig.  211. — Plan  of  the  submersible  plain  of  the  Garonne  near  Marmande. 


of  the  Garonne  with  the  dikes.  The  dike  on  the  left  hand,  which 
affects  particularly  the  railroad,  gives  way  ordinarily  at  A and  at  B. 
The  breach  at  B does  not  give  rise  to  strong  currents,  for  the  mass 
of  water  which  fills  the  space  above  the  railroad  between  the  Ga- 
ronne and  the  lateral  canal  forms  a buffer.  On  the  contrary,  the 
breach  at  A occasions  strong  currents  which  fall  directly  on  the 


CIVIL  ENGINEERING,  ETC.  793 

railroad.  Great  openings  have  been  made  for  the  disposal  of  this 
portion,  amounting  in  all  to  5,080  cubic  meters  ; the  maximum  dis- 
charge (freshet,  1875)  was  estimated  at  10,000  cubic  meters  per  second. 


iaduc  4 arches 

25^ 


riadufc  6 arches 
25? 


In  order  to  leave  more  free  space  under  these  works,  for  floating 
bodies,  and  to  present  to  the  flowing  water,  washing  the  side  slopes, 


794 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


a greater  obstacle,  the  level  of  the  rails  has  been  raised  in  the  part 
most  exposed  to  the  strong  current,  the  force  of  the  current  dimin- 
ishing from  the  Garonne  to  the  canal.  The  profile  lengthwise  is  a 
series  of  piers  united  by  slopes  of  0.004  meters.  The  soil  consists  of 
10  meters  of  alluvial  deposit  covering  a very  heavy  compact  clay 
marl  (upper  tertiary).  The  foundations  of  all  the  important  works 
are  built  1 meter  at  least  into  the  marl;  the  Garonne  bridge  is  built 
in  4 meters.  Masonry  work  was  built  under  the  three  highest  piers 
of  the  longitudinal  section,  at  slight  expense.  Iron  was  used  under 
the  lowest  pier.  The  Garonne  bridge  consists  of  four  20-meter  ellip- 
tic arches  of  5 meters  rise  ; five  elliptic  arches  of  56  meters  span  and 
10  meters  rise,  sixteen  20-meter  elliptic  arches  of  5 meters  rise.  The 
two  viaducts  at  the  end  have  arches  of  25  meters  span  and  6.25  me- 
ters of  rise,  one  of  four,  and  the  other  of  six  arches.  (Fig.  212). 

The  two  elliptic  isolated  arches  are  of  20  meters  span  and  5 meters 
rise.  The  two  jron  superstructures  are  33  meters  span.  The  foun- 
dations of  the  36-meter  arches  were  made  by  the  use  of  compressed 
air,  with  iron  caissons.  The  foundations  of  the  20-meter  arches  were 
made  by  the  same  system,  part  with  ordinary  iron  working  cham- 
bers, and  part  with  masonry  working  chambers  mounted  on  curbs. 
An  abutment  was  founded  upon  a curb  of  a rectangular  form,  this 
form  never  having  previously  been  employed.  The  curb  was  joined 
to  the  masonry  by  iron  tie-rods  4.50  meters  long  imbedded  in  the 
masonry.  For  filling,  bdton  has  given  the  best  results;  in  every 
case  the  filling  is  terminated  by  pouring  in  cement. 

(306)  The  foundations  of  twenty  such  works  were  made  by  means 
of  masonry  working  chambers,  but  of  a form  slightly  different  from 
those  previously  employed.  (Figs.  213-219). 

First,  the  bases  of  all  the  foundations  were  elliptical.  (Fig.  215). 
The  base  was  somewhat  strengthened. 

Second,  the  angle  irons  of  the  brackets  were  arranged  with  exte- 
rior wings,  and  the  curbs  were  filled  with  brick  masonry  which  gave 
them  a great  solidity.  (Fig.  216). 

Third,  the  working  chamber  of  an  ogival  form  consists  of  cement 
masonry  1 meter  thick.  The  method  of  making  these  twenty  foun- 
dations was  as  follows : 

A pier  of  about  6 meters  in  height  was  constructed,  including  the 
exterior  mastics,  leaving  the  masonry  and  mastics  to  set  for  a month 
at  least  before  sinking.  (Fig.  217). 

They  then  proceeded  to  sink  this  first  part.  (Fig.  218).  When 
this  was  at  the  bottom  they  constructed  the  rest  of  the  masonry 
and  waited  a month  again  to  make  sure  of  the  setting.  They  then 
began  with  compressed  air.  (Fig.  219).  Only  a single  severe  acci- 
dent Avas  the  sudden  fall  of  1.70  meters  of  the  foundation  in  going 
through  a layer  of  movable  gravel.  To  prevent  the  recurrence  of  a 
similar  fall  during  the  period  of  work,  they  made,  when  traversing 


t 


795 


CIVIL  ENGINEERING,  ETC. 

dangerous  layers,  sudden  changes  of  pressure  every  six  hours.  All 
the  arches  were  constructed  in  rings,  leaving  the  joint  of  rupture  on 
the  center  (as  these  centers  were  very  strong  they  did  not  key  the 
joints  of  rupture  until  after  the  second  ring  had  been  finished). 


Masonry  caissons  used  in  constructing  the  foundations  of  the  viaducts  built  to  cross  the 

SUBMERSIBLE  PLAIN  OF  THE  GARONNE. 


Figs.  213,  214,  and  215.— Longitudinal  and  transverse  sections,  and  plan  of  a pier  with  its  masonry 
compressed  air  working  chamber.; 


Fig.  216.— Detail  of  the  cutting  edge  and  wooden  curb. 


Fig.  217.— Pier  before  sinking. 


Fio.  218.— Pier  during  the  process  of  sinking. 


Fig.  219.— Pier  completely  sunk. 


The  centers  of  the  20-meter  arches  were  struck  twenty  days  after 
they  were  keyed.  Those  of  3G  meters,  forty  days  after. 

(307)  The  cost  of  the  substructure  for  the  crossing  of  the  Ga- 
ronne plain  amounts  to  3,895,950.21  francs  for  a length  of  4,338  me- 
ters, i.  e.,  898,000  francs  per  kilometer. 

The  inspectors-general  were  MM.  Croizette-Desnovers,  Vernis,  De 
la  Tournerie,  and  Renoust  des  Orgeries;  the  chief  engineers,  MM. 
Faraguet,  Cliardard,  Pugens,  and  Pettit;  the  engineers,  Bernadeau, 
Sdjournd,  and  Guibert. 


796 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


Chapter  XLII. — Oloron  Bridge  upon  the  Gave  d’Oloron 
Railway  from  Pau  to  Oloron. 

(308)  The  bed  of  the  Gave  d’Oloron,  at  the  point  where  it  is  crossed 
by  the  railroad  from  Pau  to  Oloron,  is  confined  between  two  banks 
from  15  to  18  meters  high  and  has  a width  which  varies  from  25  me- 
ters at  low  water  to  52  meters  in  freshets.  Freshets  attain  the 
height  of  5.49  meters,  with  a velocity  of  4.50  meters  per  second.  The 
bottom  of  the  bed  is  formed  of  schistose  rocks  mixed  with  banks 
of  marl  under  a thin  layer  of  sand  and  gravel.  The  difficulty  of 
crossing  the  town  of  Oloron  in  a cut  of  123,000  cubic  meters,  and  of 
establishing  a station  of  8 hectares  of  surface  at  the  end  of  the  bridge, 
required  that  the  rails  should  be  placed  23.04  meters  above  low 
water.  The  marble  quarries  in  the  vicinity  offered  excellent  ma- 
terials for  the  construction.  These  considerations  led  to  the  cross- 
ing of  the  river  with  a single  arch  of  40  meters  span,  which  allowed 
the  foundation  of  the  supports  to  be  made  almost  without  a coffer- 
dam, in  an  impermeable  soil.  The  total  length,  including  the  abut- 
ments, is  88.70  meters.  The  width  between  the  parapets  is  10  meters. 
The  two  abutments  of  the  great  arch  are  opened  by  full  centered 
arches  of  9.20  meters  span.  (Fig.  220). 

The  head  bands  of  the  great  arch  have  the  same  dimensions  as  the 
arch  itself,  1.30  meters  at  the  keystone  and  2.60  meters  at  the  joints 
at  30  degrees.  The  extrados  curve  is  the  arc  of  a circle  determined 
by  these  three  points.  Its  radius  is  24.15  meters. 

The  arch  rests  against  two  strong  cut-stone  pilasters,  tangent  to 
the  intrados  curve  near  the  springing  line.  These  pilasters  project 
0.30  meter  from  the  surface  of  the  spandrels  under  the  plinth  and 
have  a batter  of  0.05  per  meter.  The  spandrels,  on  the  contrary,  are 
vertical  and  made  of  masonry,  like  the  intrados  and  the  surfaces  of 
the  abutments. 

To  reenforce  slightly  the  arch  at  the  joint  of  rupture  the  extrados 
is  limited  by  a tangent  to  the  arc  of  a circle  above  defined,  drawn  at 
the  extremity  of  the  joint  at  45  degrees. 

The  mean  pressure  on  the  keystone  is  11.31  kilograms  per  square 
centimeter.  The  mean  pressure  on  the  joint  of  rupture  is  12.46  kilo- 
grams. A longitudinal  arch  of  1.50  meters,  with  two  arches  of  1.65 
meters  opening,  sustained  by  pillars  0.90  meter  wide  at  the  springing 
lines,  are  placed  above  the  spandrel  of  the  arch.  The  maximum 
height  of  these  pillars  is  9.01  meters,  and  their  thickness  at  the  base 
1.20  meters.  They  are  united  between  them  by  two  Stories  of  arches 
0.50  meter  wide.  The  end  abutments  are  15.30  meters  high  on  the 
right  bank  and  11.50  meters  on  the  left. 

The  center  of  the  great  arch  was  built  on  two  temporary  masonry 
piers  2 meters  thick.  25  meters  apart,  and  upon  two  wooden  piers 
placed  against  the  abutment.  The  rapidity  of  the  current  and  the 


The  center  consisted  of  five  stiff  trusses,  1.84  meters  apart,  and 
two  head  trusses  situated  at  a distance  from  the  first  of  1.1<  meters. 
This  arrangement  was  required  by  the  necessity  of  immediately  con- 


CIVIL  ENGINEERING,  ETC.  797 

rocky  bottom  would  have  rendered  the  establishment  of  intermedi- 
ate points  of  support  difficult  and  costly. 


/ 


798 


UNIVERSAL  EXPOSITION  OF  1839  AT  PARIS. 


structing  the  portion  of  the  arch  next  to  the  head  band,  on  account 
of  the  upper  voussoirs  being  single  stones  1.30  meters  long,  while 
the  body  of  the  arch  for  a length  of  8.30  meters  was  made  in  two 
rings,  each  having  half  the  thickness  of  the  arch. 

The  center  rested  on  sixty  sand  boxes,  with  cast-iron  pistons. 
The  center  was  set  up  by  means  of  a very  light  temporary  bridge 
upon  the  courses  below  the  great  bridle  pieces. 

Up  to  the  joints  of  30  degrees  the  arch  was  constructed  along  its 
whole  thickness,  then  the  center  was  loaded  with  a weight  equal  to 
one-third  of  the  weight  of  the  first  ring,  which  had  a thickness  of 
1.30  meters  at  the  30-degree  joints  and  0.05  meter  at  the  keystone. 
It  was  keyed  in  a single  point  at  the  crown. 

The  second  ring  was  constructed  from  the  springing  line  and 
keyed  like  the  first.  The  center  was  struck  fifty-nine  days  after  the 
second  ring  had  been  keyed.  The  settling  was  only  0.003  meter. 
The  settlement  on  the  center  had  been  0.03  meter. 

The  total  cost  was  407,793.46  francs,  that  is,  4,579.17  per  running 
meter. 

The  Oloron  bridge  was  projected  and  the  work  was  executed  under 
the  direction  of  MM.  Croizette-Desnoyers  and  Vernis,  general  in- 
spectors of  roads  and  bridges,  by  M.  Leraoyne,  chief  engineer,  and 
La  Riviere,  Maurer,  and  Biraben,  assistant  engineers. 

Chapter  XLIII. — The  Gravona  Bridge. 

(309)  The  Gravona  bridge  is  situated  on  the  railroad  from  Ajac- 
cio to  Corte,  about  15  kilometers  from  Ajaccio.  The  river  Gravona, 
which  takes  its  rise  in  the  high  mountains  in  the  center  of  the  island, 
is  frequently  exposed  to  freshets,  which  attain  in  this  place,  where 
the  bed  is  particularly  narrow,  a maximum  height  of  9.53  meters. 
These  special  conditions  require  the  avoidance  of  any  obstacle  what- 
ever to  the  current,  and  that  the  river  shall  be  crossed  without  any 
support  in  its  bed.  The  abundance  of  granite  in  the  vicinity  allowed 
the  work  to  be  built  of  masonry.  It  consists  of  a single  circular 
arch.  43.53  meters  span,  16.80  meters  rise,  and  22.50  meters  radius.  It 
is  founded  on  the  compact  granite  which  comes  down  to  the  water’s 
edge.  The  bridge  (Fig.  221)  has  a single  track,  and  its  width  be- 
tween the  parapets  is  4.10  meters. 

The  arch  has  a thickness  of  1.40  meters  at  the  keystone.  The  ra- 
dius of  the  extrados  is  27  meters,  and  it  has  at  the  joint  of  rupture  a 
thickness  of  2.80  meters.  It  is  covered  with  a layer  of  hydraulic 
mortar  0.10  meter  thick. 

The  spandrels  are  in  a vertical  plane ; they  are  prolonged  back 
from  the  abutments  to  the  natural  soil  by  wing  walls  projecting  0.45 
meter  from  the  spandrel  and  having  an  exterior  batter  of  0.04  meter. 
The  interior  filling  in  this  work  between  the  spandrels  is  by  means 
of  stones  carefully  arranged  by  hand.  The  work  is  surmounted  by 


799 


CIVIL  ENGINEERING,  ETC. 

a plinth  0.40  meter  high  and  projecting  0.45  meter  from  the  span- 
drel wall.  This  plinth  is  formed  of  two  courses,  and  rests  upon  a 
series  of  biackets.  On  the  plinth  there  is  a full  masonry  parapet. 
The  entire  work  is  constructed  of  granite  masonry  from  the  neigh- 


boring quarries.  The  arch  is  of  cut  stone  1.40  meters  thick  at  the 
keystone.  The  granite  material  used  in  the  arch  may  be  considered 
as  resisting  a load  of  600  kilograms  per  square  centimeter.  The 
pressures  are:  at  the  key,  26.00  kilograms;  at  the  joint  of  rupture, 
31.80  kilograms;  and  upon  the  foundation,  14  kilograms. 


800' 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


The  impossibility  of  establishing  with  security  points  of  support 
in  the  river  required  the  construction  of  a special  kind  of  center. 
A provisional  mass  of  masonry  was  therefore  raised  on  each  bank 
upon  which  was  established  the  center  supports,  having  a maximum 
span  reduced  to  29.63  meters.  For  raising  the  center  a suspension 
bridge  was  employed  made  of  two  cables,  whose  extremities  were 
made  fast  to  solid  frames  embedded  in  a coffer  covered  with  riprap. 
The  transverse  girders  were  formed  of  beams  attached  to  the  chain 
by  ropes,  and  upon  these  beams  a planking  supported  a light  rail- 
road carrying  the  materials.  Tlxe  flooring  of  this  bridge  was  7 me- 
ters below  the  intrados  at  the  key.  The  arch  was  constructed  in  two 
successive  rings  from  the  joint  at  45  degrees,  corresponding  nearly 
with  the  angle  of  sliding.  The  termination  of  the  arch  was  effected 
on  the  1st  of  August,  1884. 

The  center  was  struck  almost  automatically  on  account  of  the 
progressive  contraction  of  the  wood  under  the  action  of  heat. 

The  apparent  elasticity  of  the  arch  at  the  moment  of  placing  the 
keystone  of  the  second  course  seemed  to  indicate  that  the  center 
already  had  slightly  settled  from  the  arch.  Thirty  days  after  the 
keying  the  center  had  settled  several  centimeters.  No  settling  took 
place  in  the  arch. 

The  cost  was  119,000  francs,  that  is,  83  francs  per  square  meter  of 
elevation. 

The  projects  were  prepared  and  the  works  executed  under  the 
direction  of  MM.  Delestrac  and  Buffet,  general  inspectors,  by  MM. 
Gay,  Dubois,  and  Margerid,  chief  engineers,  and  MM.  Descubes  and 
Fonan,  assistants. 


PART  I YT— CIVIL  CONSTRUCTION  AND  ARCHI- 
TECTURE. 


Chapter  XLIV. — Specimens  of  iron  construction  in  Paris. 

(310)  The  great  retail  store  of  M.  Jaluzot,  called  Magazins  du 
Printemps,  destroyed  by  fire  in  1881,  lias  been  rebuilt  by  M.  Sedille, 
architect,  with  the  assistance  of  eminent  engineers,  both  for  the 
foundation  and  the  iron  framework. 

The  ground  has  an  area  of  3,000  square  meters,  and  it  was  re- 
quired to  make  an  available  floor  space  of  21,000  square  meters  and 
have  the  whole  well  lighted  from  the  top  and  sides. 

These  requirements  precluded  the  use  of  walls,  either  within  the 
building  or  on  the  outside. 

The  floorings  of  the  various  stories,  many  of  which  were  to  hold 
heavy  goods,  were  required  to  be  especially  strong,  and  the  loads  to 
be  placed  in  the  upper  portions  of  the  building  made  it  necessary  for 
the  architect  to  adopt  iron  as  the  material  for  the  construction  of 
the  pillars,  and  to  employ  stone  simply  for  decorative  purposes ; for 
ordinary  hard  stone  supports  a pressure  of  about  30  kilograms  per 
square  centimeter,  while  iron  will  support  from  600  to  800. 

Now,  the  load  on  some  of  the  pillars  from  7 to  8 meters  apart  was 
350,000  kilograms,  which  would  have  required  stone  pillars  more 
than  a meter  square  ; hence  iron  pillars  were  adopted. 

Again,  the  establishment  of  heavy  piers  on  isolated  spots  required 
the  foundations  to  be  made  by  sinking  pits  in  various  parts  of  the 
ground ; but  the  soil  consisted  of  fine  sand  mixed  with  water  and 
clay. 

(311)  Three  borings,  made  to  the  depth  of  35  meters,  96  meters, 
and  53  meters,  respectively,  produced  a flow  of  2,400  cubic  meters  of 
water  per  day.  At  a depth  of  2 meters  the  soil  was  sand  and  gravel 
which  showed  a density  sufficient  to  support  a load  of  from  6 to  8 
kilograms  per  square  centimeter. 

It  was  therefore  determined  to  sink  cylindrical  pits  from  2.50  or 
3 meters  in  diameter  to  the  depth  of  2 meters,  the  maximum  load 
being  350,000  kilograms  and  the  minimum  250,000. 

H.  Ex.  410 — vol  hi 51 


801 


802 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


(312)  It  now  remained  to  determine  how  these  pits  should  be  sunk. 
It  would  be  dangerous  to  use  the  ordinary  cofferdams  from  which 
the  water  is  pumped  out  and  bdton  run  in.  Such  a process,  by  re- 
moving the  very  abundant  supply  of  surface  water,  would  cause 
the  settling  of  the  surface  sand,  would  break  up  the  soil,  and  en- 
danger the  foundations  of  the  surrounding  structures.  For  this 


Fig.  222.— Transverse  section  of  the  apparatus  used  for  the  pneumatic  foundations.  A,  B,  founda- 
tion caisson ; a plate-iron  cylinder.  C.  D,  E,  F,  movable  plate-iron  bell.  G.  H,  plate-iron  deck  on  which 
the  excavation  spoil  is  heaped  to  balance  the  under  pressure  within  the  caisson.  K,  entrance  for 
workmen,  and  opening  for  the  removal  of  the  excavation  spoil.  L,  air-lock  door  giving  access  to  the 
caisson.  M,  inlet  pipe  for  the  compressed  air.  N,  movable  pipe  for  the  introduction  of  the  b6tou. 

reason  the  architect  adopted  the  method  of  sinking  them  by  com- 
pressed air,  and  employed  this  process  for  the  first  time  in  making 
foundations  in  the  city  of  Paris. 

(313)  M.  Zscliokke,  who  has  made  a specialty  of  river  and  harbor 
work  was  called  to  make  these  foundations,  which  he  did  with  great 


CIVIL  ENGINEERING,  ETC. 


803 


rapidity.  For  each  foundation  of  a pier  a cylindrical  caisson  AB 
(Fig.  222)  was  employed,  from  2.50  to  3 meters  in  diameter  and  2 
meters  high,  made  of  plate  iron  4 millimeters  thick,  strengthened 
above  with  two  circular  angle  irons  GO  by  GO,  and  at  the  lower  part, 
by  plate  iron,  200  by  10  millimeters,  forming  the  cutting  edge.  This 
caisson  was  to  pass  through  the  layer  of  water.  It  is  surmounted  by 
two  conical  frustrums,  EF  and  GH,  both  of  iron  and  united  by  an 
iron  bell,  CD,  which  is  bolted  to  the  upper  belt  of  the  caisson.  These 
two  upper  cones,  one  interior,  GH,  inclined  at  30  degrees,  the  other 
exterior,  EF,  at  GO  degrees,  formed  the  air  lock  necessary  for  the 
process.  They  are  each  furnished  with  a door  communicating  with 
the  interior  of  the  lock  at  K,  and  from  the  interior  of  the  lock  to  the 
interior  of  the  caisson  at  L.  Stopcocks  serve  to  equalize  the  pres- 
sure between  the  two  without  being  obliged  to  open  the  doors.  At 
the  upper  part  there  is  a winch  to  raise  the  buckets. 

An  India  rubber  pipe  70  millimeters  in  diameter  which  passes 
through  the  two  cones  furnishes  the  compressed  air.  at  0.5  atmos- 
phere, from  an  air  compressor.  This  air  forces  back  the  water  and 
allows  the  workmen  to  work  freely  in  the  interior  of  the  caisson 
which  .slowly  descends.  The  excavation  spoil  raised  in  the  caisson 
is  thrown  out  upon  GH,  and  thus  gives  the  caisson  an  increasing 
load  necessary  to  balance  the  under  pressure  of  the  compressed  air, 
beside  the  resistance  due  to  the  friction  of  the  ground  against  the 
iron  wall.  Before  running  in  the  bdton  the  excavation  spoil  is 
thrown  off,  being  compensated  by  the  weight  of  the  apparatus.  The 
introduction  of  the  beton  is  made  through  the  movable  tube  X,  fixed 
to  the  upper  part  of  the  cone  EF,  by  means  of  successive  lockages. 
As  it  is  introduced  it  is  well  rammed,  and  when  it  arrives  at  the  de- 
sired level  for  laying  the  stone  blocks  the  supply  of  compressed  air 
is  kept  up  for  several  hours,  to  prevent  the  water  from  rising,  and  to 
allow  the  hydraulic  mortar  time  to  set.  This  done,  it  only  remains 
to  take  away  the  double  cone  forming  the  air  lock,  and  to  remoAre  it 
to  another  caisson.  Twenty-four  hours  suffice  to  make  the  complete 
foundation  of  a pit  2.50  meters  in  diameter;  ten  hours  for  sinking 
and  excavating,  and  fourteen  hours  for  running  in  and  ramming 
the  b^ton. 

Finally,  to  avoid  the  heating  resulting  from  the  compression  of 
the  air,  a continuous  jet  of  spray  was  introduced.  These  different 
operations  terminated,  the  cones  were  taken  away,  leaving  in  the 
foundation  the  metallic  caisson  which  enveloped  the  cylindrical  col- 
umn of  beton  and  added  to  its  resistance. 

Thus  the  foundation  of  the  forty-six  iron  pillars  in  the  interior  of 
the  Printemps  were  laid.  In  like  manner  the  stone  pillars  of  the 
exterior  facades,  and  the  grand  vestibule  or  hail  were  made. 

The  loads  which  these  foundations  had  to  bear  varied  from  230  to 
350  tons.  For  this  reason,  at  certain  points  heavily  loaded,  the 


804 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


diameter  of  the  foundation  was  made  3 meters  instead  of  2.50,  the 
diameter  adopted  for  most  of  the  other  caissons. 

(414)  I ' ounclations  for  the  steam  engines. — The  use  of  dynamo- 
electric  machines  for  lighting  the  new  edifice  recpiires  a Corliss  steam 
engine  of  500  horse  power,  and  it  was  necessary  to  take  special  pre- 
cautions in  making  the  foundations  for  it.  Accordingly,  the  archi- 
tect decided  on  the  construction  of  an  iron  caisson  12.75  meters  long, 
4 meters  wide,  2 meters  high,  and  0.006  meter  thick,  to  lay  the  foun- 
dations below  the  sheet  of  water  by  means  of  compressed  air.  This 
was  successfully  accomplished  and  filled  with  a mass  of  Mton  1.20 
meters  high.  On  this  mass  stones  of  enormous  size  were  placed  to 
receive  the  supports  for  the  four  principal  shafts. 

(315)  Iron  work. — What  was  required  in  the  new  store  was  space 
and  light.  By  increasing  the  number  of  stories  upon  the  ground  of 
3,000  meters,  an  area  of  21,000  meters  of  flooring  was  easily  obtained. 


Transverse  sections  of  the  pillars  of  the  Magazin  dp  Printemps. 


w - - 

5 oo *. 

'•<  • 

_ Soo 

X 

1 

r T ; 

r 

M Son  (2  ,c5 
- to 

A 

r 

1 

r "> 

USojiK 

L. 

-j 

L -U 

L 

J 

r 

L 

Fig.  223.— Exterior.  I.  Least  loaded. 


Fig.  224.— Interior.  II.  Least  loaded 


Fig.  225.— Interior.  III.  Most  loaded. 


As  to  the  light,  it  had  to  be  obtained  through  the  sides,  and  through 
the  glazed  roof  of  the  central  nave.  Consequently  there  must  be  no 
interior  wall  and  no  exterior  wall  around  the  edifice,  but  simply 
isolated  iron  pillars  of  as  small  a number  as  possible. 

(316)  The  contract  for  the  iron  work  of  this  important  construction 
was  given  to  Baudet,  Donon  & Co.,  whose  reputation  and  great 
workshops  were  a guarantee  of  rapid  construction.  To  determine 
the  resistance  of  these  pillars  the  section  of  which  was  fixed  at  50 
centimeters  on  each  side,  in  order  to  leave  the  necessary  spaces  for 
the  conduits,  it  was  necessary  to  take  account  of  the  "exact  loads 


Paris  Exposition  op  1889— Vol.  3.  Civil  Engineering,  etc.— PLATE  XI. 


f 


IRON  FRAME  WORK  OF  A PARIS  STORE  (THE  MAGAZIN  DU  PRINTEMPS). 


805 


CIVIL  ENGINEERING,  ETC. 


whicli  the  pillars  would  have  to  support.  These  loads  are  of  two 
hinds,  the  dead  load  and  the  rolling  or  accidental  load. 

The  dead  load  is  composed  of  the  weight  of  all  the  parts  of  the 
construction  which  form  the  flooring.  The  multiplicity  of  stories  of 
small  heights  rendered  it  important  to  diminish  as  much  as  possible 
the  thickness  of  the  flooring.  The  architect  obtained  this  result  by 
using  for  floor  timbers  the  smallest  specimen  of  double  T-iron  girders 
in  use.  that  is  to  say,  T of  80  millimeters,  with  a span  not  exceeding 
2 The  hllmg  was  fOTmed  of  hollow  brick  laid  in  plaster  upon 

iron  beams  14  millimeters  thick.  For  the  calculations,  the  dead 
load  upon  the  flooring  was  estimated  at  280  kilograms  per  square 
meter;  the  accidental,  or  live  load,  at  520  kilograms. 

The  loads  on  the  different  floorings  being  thus  determined,  the 
sections  of  the  pillars  were  calculated  by  considering  them  as  built 
in  at  each  story,  on  account  of  the  beams  being  strongly  fastened  to 
their  brackets.  The  loads  may  be  thus  described: 


First.  Upper  flooring  of  the  cellar 

Second.  Of  the  ground  floor 

Third.  Mezzanine  story 

Fourth.  First  story 

Fifth.  Second  story 

Sixth.  Third  story 

Seventh.  Flooring  above  the  third  story. 

Eighth.  Roof  truss 

Ninth.  Pillars,  etc  

Total  per  square  meter 


Kilograms. 
...  1,200 
. . . 800 
. . . 800 
. . . 800 
. . . 800 
...  800 
. . . 500 
. . . 300 
, . . 600 


6,600 


(31 7)  These  pillars,  loaded  according  to  their  position,  may  be 
divided  into  three  classes: 

first.  Pillar  on  the  perimeter  (Fig.  223). 

Second.  Pillar  on  the  interior  least  loaded  (Fig  224). 

Third.  Pillar  on  the  interior  most  loaded  (Fig.  225). 


I. 


Surface  to  be  carried,  7.80  by  3.20 
165,000  kilograms. 

Web  450  by  12 

4 plates  500  by  12 

4 Angle  irons,  100  and  100,  by  12. . 
4 Angle  irons,  80  and  80,  by  10. . . . 

Total 

Load  per  square  millimeter 

45400 


meters,  = 25  square  meters.  25  by  6,600  = 


square  milimeters. . 5,400 

do 24,000 

do ...  9,600 

do 6,400 


45,400 

3.6  kilograms  to  resist  crushing. 


II.  For  an  interior  pillar  least  loaded  ~~ 


230000 


57400 


3.87  kilograms. 


III.  For  the  most  heavilv  loaded 


348000 

90400 


3.85  kilograms. 


For  the  short  double  T beams  It  (load  per  square  millimeter)  = 6.3  kilograms. 
For  the  longest  beams  R (load  per  square  millimeter)  = 6.7  kilograms. 


806 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


Strength  of  the  pillars  to  resist  rupture  hy  flexure  for  cases  I,  II, 
and  III,  calling  the  height  of  the  pillar  in  the  cellar  3 meters,  and 


its  width  0.5,  we  have  hy  Love’s  formula,  1.55+0.0005 
hence, 

I.  R = 3.6  by  1.568  = 5.75  kilograms  per  square  millimeter. 

II.  R = 3.87  by  1.568  = 6.07  kilograms  per  square  millimeter. 

III.  R - 3.85  by  1.568  = 6.03  kilograms  per  square  millimeter. 


1.568; 


PI.  XI  shows  the  frame  work  in  construction,  and  exhibits  the 
form  and  arrangement  of  the  pillars  and  floor  beams. 

Acknowledgment. — I wish  to  express  my  indebtedness  to  Messrs. 
Sedilffi  and  Baudot  for  explanations  and  documents. 


Chapter  XLV. — The  Eiffel  Tower. 


(318)  The  investigations  of  M.  Eiffel  upon  high  iron  piers  for 
railroad  viaducts  like  that  at  Garabit,  led  him  to  consider  that  such 
piers  might  be  erected  to  a height  very  much  greater  than  they  had 
yet  attained. 

The  principal  difficulty  hitherto  found  in  the  erection  of  high  iron 
piers  is,  that,  generally,  a system  of  heavy  lattice  bracing  is  placed 
on  their  faces  to  resist  the  action  of  the  wind;  as  the  pier  is  in- 
creased in  height  the  base  also  increases,  and  this  lattice  bracing, 
on  account  of  its  great  length,  becomes  of  imaginary  rather  than 
real  utility. 

There  is,  therefore,  great  advantage  in  dispensing  entirely  with 
these  large  and  heavy  accessory  pieces,  and  giving  to  the  pier  such 
a form  that  all  the  shearing  stresses  shall  be  concentrated  in  its 
edges,  these  being  reduced  to  four  great  columns  united  simply  by 
widely  separated  horizontal  bands. 

Imbued  with  these  ideas,  M.  Eiffel  made  the  calculations  for  a 
great  pier  120  meters  high  and  40  broad  at  the  base. 

These  researches  finally  led  to  the  studies  for  a tower  attaining  a 
height  of  300  meters. 

The  project  for  such  a tower  was  carefully  prepared  by  MM.  Nou- 
guier  and  Koechlin,  engineers  of  the  Eiffel  Company,  and  M.  Sau- 
vestre,  architect.  It  was  brought  before  the  French  Society  of  Civil 
Engineers  by  M.  Eiffel,  and  thus  summarily  described. 

(319)  Description  of  the  proposed  tower. — The  frame  work  con- 
sists essentially  of  four  uprights,  forming  the  edges  of  a pyramid 
with  curved  faces;  each  upright  has  a square  section  decreasing 
from  the  base  to  the  top,  and  forms  a curved  lattice  caisson  15  meters 
square  at  the  base  and  5 at  the  top. 

The  uprights  are  100  meters  apart  from  center  to  center  at  the 
base,  and  are  firmly  anchored  in  a solid  mass  of  masonry. 

At  the  first  story,  70  meters  above  the  ground,  the  uprights  are 
united  by  a gallery  15  meters  wide  running  from  pier  to  pier  around 
the  whole  construction,  and  having  an  area  of  4,200  square  meters. 


o> 

3 


o 


— 


i- 

c 

cc 

© 

ir. 

- 


c 


* 

K 


ffi 


CIVIL  ENGINEERING,  ETC. 


807 


At  the  second  story  there  is  a platform  30  meters  square.  At  top, 
a cupola,  and  a balcony  with  an  area  of  250  square  meters.  At  the 
lower  part  of  the  tower  an  imposing  arch  of  80  meters  span  and 
50  rise  is  placed  in  each  face,  which,  by  its  broad  open-work  head 
band  and  its  ornamented  and  variously  colored  spandrel,  forms  the 
principal  decorative  feature. 

(320)  Strength  and  stability  of  the  tower  ; force  of  the  wind. — The 
force  or  pressure  of  the  wind  may  be  decomposed  as  follows  : 

Suppose  for  an  instant  that  we  have  in  one  face  of  a pier  (Fig. 
226)  a simple  lattice  forming  a surface  resisting  the  shearing  stresses 
of  the  wind ; let  the  horizontal  components  of  these  stresses  be  P1, 
P“  Pm,  P,v. 

To  calculate  the  stress  in  the  three  pieces  cut  by  any  plane  M N,  it 
is  sufficient  to  determine  the  resultant  P of  all  the  exterior  forces 
acting  above  this  section,  and  to  decompose  this  resultant  into  three 
forces  passing  through  the  pieces  cut. 

If  the  form  of  this  system  is  such  that  for  each  horizonal  section 
M X,  the  two  uprights  Oa  and  Ob  intersect  on  P,  the  effort  on  the 
lattice  bar  C D is  nothing,  and  it  may  be  dispensed  with.  The  ap- 
plication of  this  principle  constitutes  one  of  the  peculiarities  of  M. 
Eiffel’s  system.  It  is  therefore  evident  that  the  direction  of  each 
element  of  the  uprights  follows  the  direction  of  a curve  traced  upon 
the  chart  (Fig.  227),  and  in  reality  this  exterior  curve  of  the  tower 
is  no  other  than  the  curve  of  the  moments  of  flexure  due  to  the 
wind. 

(321)  Hypotheses  in  reference  to  the  pressure  of  the  wind. — The 
uncertainty  of  the  effects  of  the  wind,  and  the  data  to  be  adopted 
both  as  to  the  intensity  and  the  amount  of  surface  struck,  requires 
the  adoption  of  particularly  prudent  hypotheses. 

With  regard  to  the  intensity  of  the  pressure  of  the  wind  two  sup- 
positions have  been  made.  The  first  assumed  the  wind  to  act  on  the 
tower  with  a constant  pressure  of  300  kilograms  per  square  meter; 
the  second,  that  the  intensity  increased  uniformly  from  200  kilograms 
at  the  base  to  400  at  the  top. 

(322)  As  to  the  surface  struck,  it  was  assumed,  notwithstanding  its 
apparent  exaggeration,  that  the  upper  half  of  the  tower  should  be 
treated  as  if  the  lattice  work  were  replaced  by  closed  surfaces;  that 
upon  the  intermediate  part,  where  the  open  spaces  are  much  greater, 
each  anterior  face  should  be  reckoned  four  times  the  real  surface  of 
the  iron;  below  (the  gallery  of  the  first  story  and  the  upper  por- 
tions of  the  arches)  the  anterior  surfaces  shoidd  be  counted  full ; 
finally,  at  the  base  of  the  tower,  the  uprights  should  be  counted  as 
full  and  struck  with  twice  the  force  of  the  wind. 

These  hypotheses  are  moi’e  unfavorable  than  those  usually  adopted 
for  viaducts. 

With  these  surfaces  the  calculations  have  been  made  under  both 


808 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


hypotheses  of  the  intensity  of  the  wind,  and  the  results  given  in  the 
annexed  chart  (Fig.  227)  show  that  the  two  funicular  polygons  thus 
obtained  are  nearly  identical.  In  the  hypotheses  of  the  uniform 
wind  of  300  kilograms  per  square  meter  upon  the  whole  tower,  the 
horizontal  effort  upon  the  whole  construction  is  3,284  tons,  and  its 
point  of  application  is  situated  92. 30  meters  above  the  masonry  base. 

The  overturning  moment  is  M,=  3,284  X 92.30  = 303,150  ton-meters. 

(323)  As  to  the  moment  of  stability,  the  weight  of  the  construc- 
tion is  as  follows: 


Tons. 

Metal „ 4,800 

Rubble  flooring 1,650 

Sundries 50 


Total 6, 500 


The  base  of  the  tower  being  100  meters,  the  moment  of  stability 
Ms  = 0,500  x ' = 325,000  ton-meters,  which  is  greater  than  M,. 

(324)  In  the  second  hypotheses,  i.  e.,  the  wind  varying  in  intensity 
from  200  to  400  kilograms  per  square  meter,  the  total  horizontal  effort 
is  only  2,874.4  tons,  hut  its  point  of  application  rises  to  107  meters 
above  the  masonry  base.  The  overturning  moment  in  this  case  is 
M.,  — 2,874.4  x 107  = 307,502  ton-meters.  This  is  very  nearly  the  same 
as  M„  and  is  still  below  Ms. 

(325)  Anchorage. — The  stability  is  still  further  augmented  by 
anchoring  each  of  the  four  standards  of  an  upright  to  the  massive 
base  by  means  of  iron  ties  embedded  in  a mass  of  masonry  sufficient 
to  double  the  coefficient  of  safety.  (Figs.  232  and  233). 

(320)  Deflection. — If  we  take  Claudel’s  designation  of  winds  given 
below,  the  calculated  deflection  will  be  as  follows  : 


Designation  of  the  wind. 

Velocity 
per  second. 

Pressure 
per  square 
meter. 

Deflection. 

Meters. 

Kilos. 

Meters. 

Very  strong  breeze ... 

10 

13.54 

0.038 

Reefing  breeze 

13 

19.50 

.055 

Very  strong  wind 

15 

30.47 

.086 

Gale 

30 

54.16 

.153 

Hurricane 

34 

78.00 

.221 

(327)  Resistance  of  the  tower  against  the  wind. — First  case,  wind 
300  kilograms  pressure  from  base  to  top.  Second  case,  wind  increas- 
ing uniformly  from  200  at  the  base  to  400  at  the  top. 


CIVIL  ENGINEERING,  ETC. 


809 


Corresponding  surf  aces  and  pressures. 


No.  of 
the  ele- 
ments. 

Height  of 
the  ele- 
ments of 
surface. 

Surface  of 
the  ele- 
ments. 

First  case  of  the  wind. 

Second  case  of  the  wind. 

Pressure 
per  square 
meter. 

Total 

pressure. 

Pressure 
per  square 
meter. 

Total 

pressure. 

Top. 

Meters. 

Sq.  meter. 

Kilos. 

Kilos. 

Kilos. 

Kilos. 

1 

76.0 

950 

300 

285.000 

375 

356,250 

2 

64.5 

1,004 

300 

319,21X1 

328 

348, 992 

3 

18.5 

583 

300 

174.900 

300 

174.900 

4 

11.5 

391 

300 

117, 300 

290 

113,390 

5 

39.0 

1,230 

300 

870, 800 

274 

338,004 

6 

7.0 

300 

300 

108,000 

258 

92, 880 

7 

42.0 

3,003 

300 

900.900 

242 

720,726 

8 

41.5 

3,301 

300 

1,008.300 

215 

722,015 

300.0 

3.284,400 

2,874.417 

(328)  Determination  of  the  stresses  in  the  uprights. — The  prolon- 
gation of  the  section  A B meets  the  axis  at  O,  the  point  of  application 
of  the  resultant  of  the  forces  1,  2,  3,  4,  5.  We  may  therefore  decom- 
pose this  force  of  1,267,200  kilograms  in  the  direction  of  the  uprights, 

which  gives  for  each  of  them  a stress  of  >(><  ■ kilograms. 


The  stress  in  the  lower  part  of  the  uprights  is  -~*2 3 * * * * * * * ll')">l>l>  kilograms. 
The  stress  in  the  upper  part  of  the  uprights  is  — (>*><)(HI  kilograms. 

/v 

(320)  Calculation  of  the  section  of  the  base  of  the  uprights. — Total 
weight  on  the  foundations,  0,500,000*  kilograms.  Overturning  mo- 
ment, 303,150,120. 

Load  on  the  base  of  an  upright  from  its  own  weight — 


6,500,000 

4 


1,625,000  kilograms. 


Load  on  the  base  of  an  upright  due  to  the  effect  of  the  wind — 


303,150.120 


= 1,515,750. 


2 by  100 

Total  loads,  3,140,750  kilograms. 

Section  of  a standard  at  its  base,  80,148  square  millimeters. 
Section  of  an  upright  = 80.148  by  4 = 320,502  square  millimeters. 


3 140  *50 

Load  per  square  millimeter  = f f = 0.8  kilograms  per  square 

Ot/v 

millimeter. 

M,  = 303.150,120  the  overturning  moment,  first  case. 

M„  = 307,562,619  the  overturning  moment,  second  case. 


CONSTRUCTION  OF  THE  EIFFEL  TOWER. 

(330)  The  idea  of  a tower  30o  meters  high  is  not  a new  one.  In 
1833  the  celebrated  English  engineer  Trevithick  proposed  to  erect  a 

*Tliis  refers  to  the  first  project ; the  weight  of  the  metal  in  the  actual  structure 
is  7,300,000. 


810 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


< <i>t-ii  on  tower  1,000  feet  high,  100  feet  in  diameter  at  the  base,  ancl 
12  feet  at  the  top.  But  this  work  was  never  begun. 

On  the  occasion  of  the  Centennial  celebration  in  1876  Messrs. 
Clarke,  Reeves  & Co.  proposed  to  construct  at  Philadelphia  a 
wrought-iron  tower  1,000  feet  high,  and  150  feet  at  the  base. 

In  1881  M.  Sebillot  proposed  the  erection  of  a tower  300  meters 
high  to  hyht  I aris  electrically,  but  this  plan  was  never  adopted. 

(331)  Situation.— It  was  finally  decided  that  the  tower  should  be 
built  on  the  Champs  de  Mars  in  front  of  the  Jena  bridge,  M.  Eiffel 
receiving  a subsidy  of  1,500,000  francs  and  the  tower  to  revert  to 
the  city  of  Paris  after  a lapse  of  twenty  years,  M.  Eiffel  and  his  rep- 
resentatives having  the  income  derived  from  the  tower  up  to  that 
date. 


Fig.  m— General  plan  of  the  foundations  of  the  Eiffel  tower. 


(332)  Foundations. — The  base  of  the  tower  consists  of  four  piers 
which  bear  the  names  of  the  four  cardinal  points,  the  two  next  the 
Seine  being  the  north  and  west,  the  others  being  east  and  south. 

It  was  absolutely  essential  that  the  piers  should  be  erected  on  firm 
ground  and  so  careful  soundings  were  made  to  determine  its  nature. 

(333)  Soundings. — A great  number  of  borings  in  the  Champs  de 
Mars  showed  the  strata  to  be  arranged  as  shown  in  Fig.  229,  that 
is,  the  lower  layer  consists  of  a bed  of  plastic  clay  resting  on  the 
chalk  formation  and  capable  of  supporting  3 to  4 kilograms  per 
square  centimeter. 

I his  clay  bed  slopes  slightly  from  the  Ecole  Militaire  toward  the 
Seine,  and  underlies  a bank  of  compact  sand  and  gravel,  a good  ma- 
terial for  foundations. 


CIVIL  ENGINEERING,  ETC. 


811 


Fig.  228  shows  the  general  plan  of  the  foundations.  For  the  two 
piers,  No.  2 and  3,  the  made  ground  was  7 meters  above  the  level  of 
the  Seine,  and  below  that  level  there  Avas  a bed  of  gravel  G meters 
thick  affording  favorable  conditions  for  an  excellent  foundation ; the 
piers  were  accordingly  built  upon  a layer  of  cement  concrete  2 me- 
ters thick.  (Fig.  232  and  Plate  XIII). 


Sandy 

clay. 


Limestone. 


Made 

grouDd. 


Sand 

and 

gravel. 


Plastic 

clay. 


Fig.  220.— Longitudinal  section  of  the  Champ  de  Mars  through  the  axes  of  piers  1 and  2. 


(334)  Use  of  compressed  air. — The  other  two  piers,  Nos.  1 and  4, 
were  differently  founded. 

The  bed  of  sand  and  gravel  occurred  at  the  level  22  (above  sea 
level),  that  is,  5 meters  below  the  level  of  the  Seine  (27),  and  it  was 
overlaid  by  soft  alluvial  deposits  from  the  river. 


Fig.  230.— Longitudinal  and  transverse  sections  of  the  iron  caissons. 

In  order  to  make  sure,  a preliminary  bell  or  caisson  1.50  meters 
in  diameter  (Fig.  222)  was  sunk  in  the  center  of  each  pier,  and  it 
was  ascertained  that,  below  the  sand  and  gravel,  sand,  ferruginous 
sandstone,  and  a bank  of  chloride  of  calcium  were  found  at  the  bot- 
tom of  a depression  washed  out  of  the  plastic  clay. 

There  was  no  difficulty,  therefore,  in  making  the  foundations  by 
using  compressed  air  with  four  iron  caissons  15  meters  long  and  6 


812 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


mmmm 


ip  v*^: 


•.^•5Vr.vJ 

| 

■ ! 


m/m 

mm. 


mmm}, 


v/Mv\ 


Eiffel  Tower. 


Fig.  231.— View  of  a caisson  for  making  the  foundations  of  the  Eiffel  Tower  by  means  of  com- 
pressed air.  Section  showing  the  underground  work  and  the  shafts  for  the  men  and  the  materia's. 


■MB' 


Paris  Exposition  of  1889— Vol.  3.  Civil  Engineering,  etc.— PLATE  XII. 


THE  EIFFEL  TOWER.  IRON  CAISSONS  USEO  WITH  COMPRESSED  AIR  IN  BUILDING  THE  FOUNDATIONS  OF  A PIER. 


CIVIL  ENGINEERING,  ETC.  813 

meters  vide  for  each  pier,  and  sunk  5 meters  below  the  level  of  the 

river. 

Figs.  230  and  231  show  the  arrangement  and  dimensions  of  one 
of  these  caissons,  and  Plate  XII  shows  all  four  caissons  of  one  of  the 
piers,  in  the  process  of  sinking. 

(335)  Description  of  the  ironwork. — Each  of  the  four  uprights  of 
the  tower  is  a huge  frame  15  meters  square  whose  edges  transmit 
the  pressure  to  the  ground  by  masses  of  masonry  placed  under 
each;  there  are  four  of  these  masses  for  each  pier.  The  top  of  each 
of  the  masses,  which  takes  the  thrust,  is  at  right  angles  to  the  direc- 
tion of  the  edges  of  the  upright;  the  mass  itself  is  pyramidal  in 
form,  having  its  vertical  face  in  front  and  its  oblique  face  behind. 
Its  dimensions  are  so  calculated  as  to  bring  the  resultant  of  the 
oblique  pressures  to  a point  very  near  the  center  of  the  foundation. 

This  oblique  pressure  amounts  to  565  tons  without  that  of  the 
wind,  and  875  with  that  of  the  wind. 

(336)  Details  of  the  foundation. — Upon  the  bottom  of  piers  Xos. 
1 and  -1,  i.  e.,  at  a depth  of  14  meters,  the  vertical  pressure  is  3,320 
tons  with  the  wind ; this,  spread  over  a surface  of  90  square  meters, 
gives  a load  of  3.7  kilograms  per  square  centimeter. 

Upon  piers  2 and  3 the  pressure  on  the  ground  at  a depth  of  9 me- 
ters is  1,970  tons,  which,  spread  over  a surface  of  60  square  meters, 
gives  a pressure  of  3.3  kilograms  per  square  centimeter. 

The  masses  of  concrete  are  10  meters  long  by  6 meters  wide,  ar- 
ranged as  in  Fig.  232.  The  concrete  is  made  of  250  kilograms  of 
Boulogne  cement  for  each  cubic  meter  of  sand.  The  masonry  is  of 
Souppes  stone  set  in  the  sand  cement.  The  use  of  cement  was 
requisite  for  attaining  a rapid  setting,  thus  avoiding  any  settling. 

At  the  center  of  each  mass  two  great  anchor  bolts  7.80  meters  long 
and  0.10  meter  in  diameter  are  imbedded,  which,  by  means  of  two 
iron  I bars  and  anchorage  plates,  hold  on  to  the  principal  portion  of 
the  masonry  (Fig.  233). 

This  anchorage,  not  necessary  for  the  stability  of  the  tower,  which 
is  maintained  by  its  own  weight,  gives  an  excess  of  security  against 
overturning,  and,  moreover,  it  was  utilized  in  the  erection  of  the 
oblique  standards. 

The  masonry,  subjected  to  a load  of  from  4 to  5 kilograms  per 
square  millimeter,  is  capped  by  two  courses  of  cut  stone  from  Chateau 
Landon,  having  a resistance  of  1,235  kilograms  per  square  centime- 
ter. The  pressure  under  the  iron  shoes  is  not  more  than  30  kilo- 
grams per  square  centimeter,  hence  the  coefficient  of  safety  is  40. 

It  may  be  seen  from  these  figures,  and  from  the  materials  selected, 
that  the  foundations  have  been  so  laid  that  there  can  be  no  doubt  as 
to  their  perfect  security. 

Besides  the  separate  foundations  for  each  standard  there  is  a ma- 


814 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


sonry  base,  carrying  no  load,  but  designed  to  support  the  metal 
moldings  which  decorate  the  pedestal  of  the  uprights. 

The  walls  which  carry  this  pedestal  are  laid  on  arches  and  form  a 
square  26  meters  on  a side,  the  whole  of  the  substructure  being  tilled 
with  earth  except  those  piers  in  which  chambers  are  reserved  for  the 
elevator  engines  and  boilers  (PI.  XIII). 

(337)  The  two  lightning  conductors  for  each  pier  are  carried  down 
in  cast-iron  pipes  0.50  meter  in  diameter  and  18  meters  long,  which 

V 


Fig.  232.— Plan,  and  section  along  A B,  of  pier  No.  1. 

are  sunk  below  the  water-bearing  stratum  and  are  in  direct  com- 
munication with  the  ironwork  of  the  tower. 

(338)  The  hydraulic  jack  of  800  tons. — Before  describing  the  erec- 
tion of  the  tower  it  may  not  be  oiit  of  place  to  give  an  account  of 
the  powerful  hydraulic  jack  used  to  adjust  the  heavy  standards. 

To  be  perfectly  sure  that  the  four  supports  of  the  tower  shall  be 
in  exactly  the  same  horizontal  plane,  a space  has  been  provided  un- 
der each  of  the  shoes  of  a standard  in  which  a hydraulic  jack  of  800 
tons  power  could  be  placed  so  as  to  raise  or  lower  any  upright  in  the 


THE  EIFFEL  TOWER.  VIEW  OF  A PIER  WITH  ITS  INCLOSING  WALL. 


CIVIL  ENGINEERING,  ETC. 


815 


structure  for  the  insertion  of  steel  strips  or  wedges  between  the  bed- 
plate and  the  shoe.  Figure  237  shows  the  jack  in  section,  and  fig- 
ure 238  taken  from  La  Nature,  shows  it  in  operation.  The  cyl- 


Fig.  233.— Anchorage  of  the  foundations.  Details:  showing  one  of  the  cylindrical  base  plates  2.16 
by  .36  meters  (weighing  5}  tons)  for  supporting  the  cylindrical  flanged  shoe.  0.612  meter  in  diameter 
bolted  to  the  standard.  An  800-tou  hydraulic  jack  is  placed  in  the  hollow  space  below  the  shoe,  for 
raising  and  supporting  the  standard  (see  p.  821).  Steel  strips  or  wedges  ate  inserted  between  the  up- 
lter  rim  of  the  base  plate  and  the  flange  of  the  shoe,  to  keep  the  standard  at  the  proper  height. 

inder  is  of  wrought  iron  95  millimeters  thick  and  the  piston  is  430 
millimeters  in  diameter. 


816 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


(339)  Erection  of  the  first,  story. — By  the  end  of  June,  1887,  the 
foundations  were  completed  and  the  erection  of  the  ironwork  began. 
The  lower  parts  of  the  columns  were  erected  by  braced  shears  22  me- 


ters high,  in  the  form  of  the  letter  A.  They  were  made  of  timber 
and  provided  with  a pulley  at  the  top,  over  which  a chain  passed  to 
a winch  on  the  ground  (Fig.  234). 


CIVIL  ENGINEERING,  ETC. 


817 

The  sections  of  the  standards,  in  the  form  of  caissons  0.80  meter 
square,  weighing  from  2,500  to  3,000  kilograms  each,  were  success- 
fully placed  on  each  other  and  joined,  first  by  pins,  then  by  bolts. 
After  the  sections  came  the  latticework  and  braces  uniting  the  por- 
tions of  the  standards  already  erected,  fixing  them  in  their  relative 
positions  and  consolidating  the  whole  structure. 

Behind  the  gangs  of  adjusters  came  the  riveters,  who  removed 
the  bolts  and  replaced  them  by  rivets  driven  hot,  forming  the  per- 
manent junction  between  the  pieces.  When  the  structure  had 
reached  the  height  of  15  meters,  the  shears  were  replaced  by  special 
cranes.  The  inclination  of  the  standards  naturally  tended  to  over- 
set them,  but  this  tendency  would  not  be  effective  until  a height 
computed  to  be  30  meters  was  reached;  so  that  up  to  this  height  the 
standards  could  be  erected,  so  far  as  their  stability  was  concerned, 
just  as  if  they  were  vertical.  Besides  the  calculated  theoretical 
security,  there  was  that  resulting  from  the  anchorage,  which  was 
more  than  sufficient  in  this  case  to  prevent  any  movement. 

The  erection  proceeded  steadily  until  the  height  of  30  meters  was 
reached.  The  weight  of  the  pieces  already  placed  in  position  ex- 
ceeded 1,450  tons. 

(340)  Erecting  scaffoldings. — To  continue  the  erection,  wooden 
scaffoldings  30  meters  high  were  built  on  piles,  and  planted  so  as  to 
sustain  at  their  tops  the  three  interior  standards  of  each  pier.  At 
the  top  of  each  scaffolding  was  a strong  platform  on  which  were 
placed  sand  boxes  such  as  are  used  on  the  centering  of  arched 
bridges. 

Accessory  brackets,  which  were  afterwards  removed,  were  at- 
tached to  the  standards,  their  horizontal  faces  resting  on  the  sand 
boxes,  thus  forming  the  support  of  the  iron  pier  on  the  wooden 
scaffolding.  This  support  once  obtained,  the  work  of  erection  went 
on  up  to  the  level  of  the  first  story  of  the  tower. 

The  sand  boxes  afforded  a means  of  rectification  in  case  of  any 
deviation  of  the  structure  from  its  true  position.  If  the  column  re- 
quired to  be  lowered  a little,  some  of  the  sand  could  be  run  out,  and 
the  iron  work  then  sank  to  the  desired  position.  If,  on  the  contrary, 
the  column  had  to  be  raised,  it  was  easily  done  by  hydraulic  jacks 
placed  on  the  platform  beside  the  sand  boxes,  and  acting  against  the 
temporary  bracket.  In  this  way  the  work  was  under  perfect  con- 
trol. 

In  the  construction  of  the  twelve  scaffoldings  just  described,  600 
cubic  meters  of  wood  were  used,  and  the  erection  was  continued  to 
a height  of  50  meters.  At  this  level  the  horizontal  girders  were 
laid,  uniting  the  four  piers  and  forming  the  first  story. 

The  special  cranes  which  were  used  had  a range  of  12  meters:  this 
was  sufficient  to  be  within  reach  of  the  four  standards.  The  cranes 
had  a power  of  4 tons  each,  and  were  worked  upon  the  inclined 
girders  forming  the  guides  for  the  elevators. 

H.  Ex.  410 — vol  iii 52 


818 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


When  the  piers  had  attained  a height  of  55  meters  the  first  great 
belt  of  horizontal  girders  was  put  in,  running  from  pier  to  pier. 
These  girders,  7.50  meters  high  and  weighing  70  tons  each,  were  so 
constructed  as  to  adapt  them  to  the  inclined  faces  of  the  converging 
columns.  These  conditions,  in  addition  to  the  great  height  at  which 
they  were  to  be  placed,  rendered  it  necessary  to  erect  for  this  purpose 
a new  scaffolding  45  meters  high,  with  a platform  25  meters  long. 
Four  such  scaffoldings  were  erected,  one  for  each  face  of  the  tower. 

The  central  parts  of  each  of  the  horizontal  girders  were  hoisted 
and  riveted  on  these  scaffoldings;  the  adjacent  portions  were  then 
added  to  the  right  and  left  so  as  to  unite  the  four'  piers,  the  opera- 
tion being  carried  on  simultaneously  for  all  four  faces. 

Plate  XIV  is  a near  view  of  this  scaffolding  and  its  superimposed 
girder.  When  these  girders  were  joined  together  they  formed  a 
strong  horizontal  frame  which  took  the  thrusts  due  to  the  obliquity 
of  the  four  piers. 

(341)  77/e  erecting  cranes. — We  shall  now  describe  the  construction 
of  the  erecting  crane  above  alluded  to.  Up  to  a distance  of  15  meters 
the  pieces  were  raised  by  shears  and  winches,  but  when  that  height 
had  been  reached  the  following  special  crane  was  devised  by  MM. 
Guyenet  and  Eiffel,  which  is  thus  described  by  M.  Nansouty:  It 
consists  (Fig.  235)  of  a long  jib,  turning  on  a pivot  mounted  on  a 
frame  having  the  form  of  a triangular  pyramid  upside  down.  The 
pivot  is  placed  in  the  axis  of  the  pyramid,  with  the  pivot  step  at  the 
apex.  The  base  of  the  pyramid  is  the  operating  platform,  and  one 
of  the  sides  of  this  base  is  connected  to  a frame  formed  of  two  lon- 
gitudinal and  two  transverse  beams.  This  last  frame  supports  the 
whole  weight,  and  transmits  it  to  the  inclined  elevator  guides  which 
wei’e  erected  with  the  piers.  The  flanges  of  these  guides  are  pierced 
with  holes  at  equal  distances.  Similar  holes  are  bored  in  the  longi- 
tudinal beams  of  the  frame  carrying  the  crane;  by  means  of  these 
holes  the  two  are  bolted  together. 

(342)  Method  of  raising  the  crane. — When  all  the  pieces  within  the 
range  of  the  crane  had  been  raised  and  riveted  together,  it  was 
necessary  to  raise  the  crane  in  its  turn;  this  was  accomplished  thus': 
A strong  iron  beam,  through  the  center  of  which  passed  a large 
screw,  is  bolted  horizontally  upon  the  guides  at  about  2.50  meters 
above  the  crane  frame.  The  screw  passes  through  the  frame,  and  is 
secured  by  a nut.  Now  if  the  bolts  are  withdrawn  from  the  frame 
and  the  guides,  the  crane  will  hang  from  the  iron  beam  suspended 
by  the  screw.  By  turning  the  nut,  the  frame  slowly  ascends  to  its 
new  position,  the  bolts  are  replaced,  and  the  work  goes  on.  When 
the  crane  is  again  to  be  raised  (supposing  the  nut  to  be  near  the  end 
of  its  course)  the  crossbar  is  detached,  carried  up,  again  bolted  to 
the  guides,  the  screw  put  in,  and  the  process  is  repeated. 

Two  jacks  were  placed  under  the  frame  in  case  of  the  rupture  of 
the  principal  screw. 


Paris  Exposition  of  1889— Vol.  3. 


Civil  Engineering,  etc.  — PLATE  XIV. 


JF 

NjgQ 

■ ' W 

THE  EIFFEL  TOWER.  NEW  SCAFFOLDING,  45  METERS  HIGH,  USED  IN  JOINING  THE  ISOLATED  PIERS. 


CIVII.  ENGINEERING,  ETC 


819 


Fig.  335.— The  erecting  cranes  especially  devised  by  MM.  Guyeuet  and  Eiffel,  used  iu  the  erection  of  the  first 

and  second  stories . 


820 


UNIVERSAL  EXPOSITION  OE  18S9  AT  PARIS, 


Fig.  230. — View  of  the  fir>t  story,  showing  one  of  the  four  piers  of  the  tower  and  the  shelter  for  the 
portable  hoisting  eugine,  the  circular  railroad,  etc. 


Paris  Exposition  of  1889— Vol.  3. 


Civil  Engineering,  etc.— PLATE  XV. 


THE  EIFFEL  TOWER.  DETAILS  OF  THE  IRONWORK  OF  THE  STRUCTURE 


CIVIL  ENGINEERING,  ETC.  821 

Another  peculiarity  of  this  crane  is  the  mechanism  by  which  the 
range  is  changed.  This  is  effected  as  follows 

The  ties  of  the  jib  are  attached  to  an  axle  mounted  on  rollers  and 
moving  vertically  on  the  crane  post  by  means  of  a screw  and  nut. 
This  simple  device  allows  the  range  of  the  loaded  jib  to  vary  from 
3 to  12  meters. 

It  is  susceptible  of  yet  another  movement  about  a horizontal  axis 
by  which  its  verticality  is  assured  whatever  be  the  inclination  of  the 
guides  upon  which  the  frame  moves.  This  is  accomplished  by  a 
screw  fixed  to  the  frame,  which  drives  a nut  placed  in  the  pivot  step. 
Again,  the  suspending  hook  is  furnished  with  a hand  screw.  The 
pieces  to  be  riveted  may,  so  to  speak,  be  mathematically  adjusted. 

Four  of  these  cranes  were  used  upon  the  four  piers  up  to  the  height 
of  150  meters.  Each  one  weighed  12  tons  and  could  lift  4 tons. 

(343)  Erection  of  the  first  and  second  stories. — The  piers  between 
the  first  and  second  stories  were  rapidly  erected  by  the  same  method 
as  that  employed  below,  i.  e.,  by  means  of  four  cranes  working  on 


Fig.  237. — One  of  the  800-ton  hydraulic  jacks. 

the  elevator  guides.  But  a new  arrangement  was  made,  after  the 
completion  first  story,  for  lifting  the  material,  the  distance  to  the 
ground  being  too  great  for  one  set  of  cranes  to  lift  it  to  its  position. 

On  the  first  story  a circular  railroad  was  laid  down,  and  a crane 
set  up  driven  by  a portable  engine  of  10-liorse  power,  which  lifted 
the  materials  from  the  ground  and  deposited  them  on  cars,  by  which 
they  were  carried  to  one  of  the  four  cranes  which  raised  them  to 
their  final  position.  (Fig.  236  and  PI.  XV). 

The  work  advanced  with  such  rapidity  that  on  the  14th  of  July, 
1888.  the  fireworks,  celebrating  the  national  fete,  were  discharged 
from  the  second  platform,  115  meters  above  the  ground. 

(344)  Use  of  the  800 -ton  jack. — “When  preparations  were  made  to 
join  the  four  pillars,  in  pairs,  by  horizontal  beams,  above  the  second 
story,  it  was  found,  as  had  been  the  case  on  the  first  story,  that  there 
was  a slight  difference  between  the  piers.  The  difference  arose  from 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS, 


822 

the  fact  that  the  piers  2 and  3 were  a little  higher  than  the  others, 
the  difference  being  between  5 and  6 millimeters.  As  no  alteration 
of  the  parts  could  be  made  on  the  spot,  the  discrepancy  was  corrected 


by  lowering  these  two  piers  and  slightly  widening  the  distance  be- 
tween them.  This  operation  was  affected  by  means  of  the  hydraulic 
jacks  above  described.”*  (Figs.  237  and  238.) 


* Tessandier. 


Fig.  938. — Operation  of  lifting  one  standard  of  the  tower  by  an  hydraulic  jack,  for  the  purpose  of  driving  in  the  wedges. 


CIVIL  ENGINEERING,  ETC 


823 


(345)  The  erecting  cranes  above  the  second  story. — Above  the  sec- 
ond story,  i.  e.,  above  115  meters,  considerable  modification  had  to 
be  made  in  the  system  of  erection.  (Fig.  239  and  PI.  XVI). 


Fio.  *239.— Arrangement  of  the  crane  for  constructing:  the  tower  above  the  second  story.  Height  215  meters. 

December.  1S88. 


824 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


The  oblique  elevator  guides  no  longer  exist,  but  are  replaced  by 
vertical  ones  belonging  to  another  system  (Edoux).  This  system  was 
introduced  because  the  curved  form  of  the  tower,  by  bringing  the 
columns  together,  had  considerably  reduced  the  horizontal  section. 
Instead  of  four  cranes,  two  were  sufficient.  To  support  these  two 
cranes  and  provide  a substitute  for  the  elevator  guide  ways,  M.  Eif- 
fel made  use  of  the  vertical  guide  pillars  introduced  between  the 
second  story  and  the  top  of  the  tower.  The  cranes  were  like  those 
already  used,  but  so  modified  as  to  adapt  them  to  be  hoisted  against 
a vertical  guide  instead  of  resting  on  the  inclined  ones.  To  balance 
them  they  were  fixed  back  to  back  on  the  central  elevator  guide 
pillar.  To  increase  the  surface  of  support  three  iron  frames  were 
also  bolted  to  the  pillar.  These  frames  were  3 meters  high,  and  wide 
enough  to  allow  the  crane  frame  to  be  bolted  to  their  vertical  sides. 
Safety  appliances  were  used  as  before,  and,  in  addition,  the  cranes 
and  auxiliary  frames  were  firmly  united  together  by  a system  of 
temporary  beams,  so  as  to  form  one  solid  structure. 

A whole  panel  of  the  tower,  10  meters  in  height,  could  be  erected 
without  shifting  the  cranes. 

The  three  squares  thus  placed  one  above  another  formed  a vertical 
road  of  9 meters,  upon  which  the  cranes  could  move  by  the  lifting 

screws. 

(346)  Method  of  shifting  the  cranes. — When  a crane  had  traveled 
up  the  three  sets  of  squares  and  had  to  go  higher,  another  set  of 
three  squares  was  placed  in  position,  the  crane  was  then  moved  up. 
and  the  first  three  squares  were  free  to  be  used  subsequently.  Jacks 
were  placed  under  the  squares  as  well  as  under  the  cranes,  so  that  in 
case  of  the  failure  of  the  bolts  the  cranes  would  remain  in  position 
(PI.  XVI). 

The  time  required  to  make  the  shift  from  one  panel  to  another 
was  about  48  hours,  a short  time  when  it  is  considered  that  the 
total  weight  to  be  moved  amounted  to  45  tons. 

The  erection  above  the  second  story  may  be  thus  summed  up  : A 
steam  winch  on  the  first  story  raised  the  material  from  the  ground, 
a second  winch  of  the  same  kind  on  the  second  story  raised  it  to  this 
level,  i.  e.  1 15  meters.  A third  steam  winch,  set  up  on  an  interme- 
diate flooring  of  the  Edoux  elevator,  197  meters  high,  brought  the 
pieces  to  the  cranes,  which  put  them  in  position. 

(347)  Protection  of  the  workmen. — The  workmen  were  provided 
with  movable  platforms  furnished  with  a hand  rail  and  screen. 
These  were  first  placed  in  position  by  carpenters,  and  occupied  succes- 
sively by  the  adjusters  and  riveters.  Only  one  accident  happened  by 
falling  and  that  was  at  the  beginning  of  the  work. 

(348)  Top  of  the  tower. — The  upper  portion  of  the  tower  termi- 
nates in  a cornice,  supporting  the  campanile  and  the  light-house. 
The  lower  part  of  the  campanile  consists  of  a covered  gallery,  16  me- 


Paris  Exposition  of  1889— Vol.  3.  Civil  Enoineering  etc. — PLATE  XVI. 


THE  EIFFEL  TOWER.  THE  ERECTING  CRANE  USED  ABOVE  THE  SECOND  STORY. 


CIVIL  ENGINEERING,  ETC. 


825 


ters  on  each  side,  and  will  accommodate  800  persons.  It  is  fitted  all 
around  with  glazed  sashes,  which  can  be  opened  or  closed  at  will, 
the  closing  of  the  windows  being  necessary  in  strong  winds.  (Fig. 
240). 


Fir,.  240.— Campanile  of  the  tower. 


The  summit  of  the  tower,  formed  of  four  lattice  arches  placed 
diagonally  to  the  square  section,  supports  the  light-house. 

Above  the  cupola  is  a small  terrace  1.40  meters  in  diameter,  to 
which  access  is  obtained  by  a ladder  in  the  lantern.  This  terrace, 


820 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


which  is  300  meters  above  the  ground,  is  specially  designed  for  the 
anemometers  and  other  meteorological  instruments. 

(349)  Staircases. — In  the  east  and  west  piers  there  are  straight 
staircases  1 meter  wide,  with  numerous  landings,  giving  easy  access 
to  the  first  floor  and  consisting  of  three  hundred  and  eighteen  solid 
oak  steps.  The  former  is  used  for  descending  and  the  latter  for 
ascending,  and  it  is  estimated  that  a file  of  2,000  persons  per  hour 
could  be  accommodated  by  them. 

From  the  first  to  the  second  story  a spiral  staircase,  0.60  meter 
wide,  is  arranged  in  each  of  the  piers  ; two  of  these  staircases  are  for 
the  ascending  and  two  for  the  descending  visitors.  They  also  will 
accommodate  2,000  persons  per  hour. 

From  the  second  story  to  the  top  there  is  a spiral  staircase  160 
meters  high,  which  is  simply  a service  staircase  and  not  open  to  the 
public. 

(350)  Arrangement  of  the  first  story. — Upon  the  first  story,  which 
covers  an  area  of  4,200  meters,  an  arcaded  open  gallery  is  arranged 
for  visitors  who  wish  to  enjoy  the  view  of  Paris,  its  environs,  and 
the  exhibition.  This  promenade  is  283  meters  long  and  2.60  meters 
wide.  There  are  also  four  large  restaurants,  capable  of  containing 
from  500  to  600  persons  each.  They  are  built  in  different  styles  of 
architecture  and  are  called  the  Russian,  the  Anglo-American,  the 
Alsace-Lorraine,  and  the  French  restaurants. 

A general  view  of  the  lower  part  of  the  tower  and  the  first  story 
is  given  Plate  XVII. 

(351)  7 he  second  story  has  a surface  of  1,400  square  meters.  It' 
has  a covered  gallery  forming  a second  promenade  150  meters  long 
and  2.60  meters  wide.  The  central  part  contains  the  stations  for  the 
elevator,  and  at  one  end  is  the  office  of  the  newspaper  printed,  stereo- 
typed. and  published  here,  called  the  “Figaro  de  la  Tour  Eiffel,” 
the  rotary  printing  press  being  worked  by  a gas  motor. 

(352)  The  third  story  is  octagonal  in  shape,  consisting  of  four  sides 
12  meters  in  length  and  four  small  ones  of  2 meters. 

An  iron  staircase  of  ten  steps  leads  up  to  the  private  rooms  of  M. 
Eiffel,  and  to  those  devoted  to  scientific  observations.  From  these  a 
straight  staircase  of  thirty  steps  leads  up  to  the  springing  lines  of 
the  iron  lattice  arches  supporting  the  campanile;  thence  a spiral 
staircase  leads,  at  the  top  of  these  arches,  to  an  iron  cylinder  contain- 
ing a ladder  of  twenty  steps  leading  to  an  octagonal  lodge  with  a 
balcony.  Through  an  iron  trapdoor  at  the  top  of  ten  steps  more 
we  come  into  the  lantern  itself.  Passing  through  this,  up  one  more 
ladder,  we  come  out  upon  a small  balcony  containing  the  flagstaff, 
and  at  a height  of  300  meters  above  the  ground. 

(353)  The  elevators. — Independently  of  the  staircases,  the  ascent  is 
facilitated  by  a certain  number  of  elevators  of  different  systems,  viz: 
(1)  The  Roux-Combaluzier  and  Lepape  system;  (2)  the  Otis;  (3)  the 
Edoux. 


Paris  Exposition  of  1889— Vol.  3.  Civil  Engineering,  etc.— PLATE  XVII. 


THE  EIFFEL  TOWER.  THE  FIRST  STORY. 


CIVIL  ENGINEERING,  ETC. 


827 

From  the  ground  to  the  first  story  there  are  four  elevators,  two  on 
Roux-Combaluzier  and  Lepape  system,  and  two  on  the  Otis  system. 
From  the  first  to  the  second  stories  the  ascent  is  effected  by  the  two 
Otis  elevators,  which,  run  continuously  from  the  ground  to  the  second 
story. 

Finally,  from  the  second  story  to  the  third,  the  Edoux  system  is 
used.  Its  starting  point  is  from  a platform  erected  halfway  between 
the  second  and  third  stories.  It  is  worked  by  water  power  with  a 
vertical  piston  having  a cage  on  the  top.  This  cage  affords  the  means 
of  transit  to  the  third  story,  a distance  of  80  meters  above  the  inter- 
mediate platform.  It  is  attached  by  chains  to  a second  cage  forming 
a counterpoise.  This  cage  brings  the  passengers  from  the  second 
story,  80  meters  below,  up  to  the  intermediate  platform.  In  this 
way  the  passengers,  by  changing  from  one  cage  to  the  other  at  the 
intermediate  platform,  make  the  ascent  of  1G0  meters  from  the  sec- 
ond to  the  third  story. 

(354)  Time  of  ascent. — The  Roux-Combaluzier  and  Lepape  system 
takes  100  passengers,  who  are  landed  at  the  first  story  within  the 
minute,  at  a speed  of  1 meter  per  second. 

The  Otis  elevator  cage  holds  50  passengers,  but  has  an  ascensional 
velocity  of  2 meters  per  second. 

The  Edoux  elevator  cage  accommodates  63  persons,  the  ascensional 
velocity  is  0.90  meter  per  second,  and  the  time  is  1|  minutes  for  each 
course  and  1 minute  for  changing  cages,  i.  e.,  4 minutes  for  the  as- 
cent from  the  second  to  the  third  platform. 

All  the  elevators  are  furnished  with  safety  apparatus.  They  are 
operated  by  hydraulic  power,  the  water  furnishing  this  power  being 
raised  by  steam  pumps  of  300  horse  power. 

The  elevators  can  take  up  to  the  first  and  second  stories  2,350 
persons  per  hour,  and  750  persons  up  to  the  third,  the  complete  as- 
cent occupying  7 minutes.  By  means  of  the  staircases  and  elevators 
combined  the  tower  can  be  visited  by  5,000  persons  per  hour. 

The  mechanical  features  of  these  elevators  are  described  in  the 
report  on  class  52. 

(355)  Verification  of  the  verticality  of  the  tower. — This  was  ac- 
complished when  the  tower  had  attained  a height  of  220  meters  by 
MM.  Thuasne  and  Seilhac.  This  verification  consisted  in  observing 
whether  the  median  lines  on  each  face  of  the  tower  were  situated  in 
the  principal  planes  of  the  tower.  By  a median  line  of  a surface  is 
meant  a line  situated  in  a vertical  plane  and  passing  through  the 
center  of  gravity  of  that  surface.  A principal  plane  is  a vertical 
plane  passing  through  the  lines  A A (Figs.  241,  242).  For  this  pur- 
pose points  a,  h,  c,  d,  e,f,  and  the  intersection  of  the  diagonals  of  the 
lattice  situated  upon  the  median  lines  of  the  four  faces  were  selected. 

The  median  lines  being  thus  traced  on  the  tower,  the  operation 
consisted  in  observing,  with  a theodolite  placed  in  the  plane  A A 


828 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS, 


and  properly  adjusted,  whether  the  points  a,  b,  c,  cl,  e,  f coincided 
with  the  vertical  wire  of  the  telescope  when  rotated  in  a vertical 
plane. 

Verification  of  the  vertically  of  the  tower. 


if 


-o 


Fig,  242.— Plan. 


CIVIL  ENGINEERING,  ETC. 


829 


These  observations  were  made  upon  each  of  the  four  planes  (4-1), 
(1-2).  (2-3),  (3-4)  at  points  situated  upon  the  lines  A A,  A A at  dis- 
tances from  the  axis  of  the  tower  varying  from  100  to  300  meters. 

One  of  these  stations  of  observation  was  upon  the  Jena  bridge 
about  250  meters  from  the  axis  of  the  tower. 

The  vertical  wire  of  the  telescope  was  found  to  coincide  absolutely 
with  all  the  points  a,  b,  c,  d,  e,  and  the  crossings  of  the  diagonals; 
hence  all  these  points  were  in  the  principal  plane.  Similar  observa- 
tions made  at  three  other  stations  showed  the  tower  to  be  abso- 
lutely vertical. 

(35G)  Uses  of  the  tower. — M.  Eiffel  thus  described  the  uses  of  the 
tower  in  an  address  to  the  members  of  the  “ Socidtd  centrale  du  Tra- 
vail Professionnel 

The  construction  of  the  tower  will  enable  us  to  observe,  with  new  effects  of  light 
a prospect  of  incomparable  beauty,  before  which  no  one  can  fail  to  be  deeply  im 
pressed  with  the  grandeur  of  nature,  and  the  power  of  man.  But  besides  its  soul 
inspiring  prospects,  the  tower  will  have  varied  applications  for  our  national  defense 
as  well  as  in  the  domain  of  science. 

(357)  Strategical  operations. — “ In  case  of  war  or  siege  it  would  be  possible  to 
watch  the  movements  of  an  enemy  within  a radius  of  70  kilometers,  and  to  look  far 
beyond  the  heights  on  which  our  new  fortifications  are  built.  If  we  had  possessed 
the  tower  during  the  siege  of  Paris,  in  1870,  with  its  brilliant  electric  lights,  who 
knows  whether  the  issues  of  that  contest  would  not  have  been  entirely  changed? 
The  tower  would  have  provided  the  means  of  easy  and  constant  communication 
between  Paris  and  the  provinces  with  the  aid  of  optical  telegraphy,  the  processes 
of  which  have  attained  such  remarkable  perfection”.  (Nansoutv.) 

It  is  situated  at  such  a distance  from  the  defensive  forts  as  to  be  out  of  the  reach 
of  the  batteries  of  the  enemy. 

(358)  Meteorological  observations. — It  will  be,  moreover,  a wonderful  meteorologi- 
cal observatory  in  which  may  be  studied  the  direction  and  force  of  the  atmospheric 
currents,  the  electrical  state  and  chemical  composition  of  the  atmosphere,  its  hy- 
grometry,  etc. 

(359)  Astronomical  observations. — As  regards  astronomical  observations,  the 
purity  of  the  air  at  such  a height,  the  absence  of  the  mists  which  often  cover  the 
lower  horizons  in  Paris,  will  allow  many  physical  and  astronomical  observations  to 
be  made  which  would  be  often  impossible  in  our  region. 

(360)  Scientific  experiments  maybe  made,  including  the  study  of  the  fall  of  bodies 
in  the  air,  the  resistance  of  the  air  according  to  speed,  certain  laws  of  elasticity,  the 
study  of  the  compression  of  gas  and  vapors  by  an  immense  mercurial  manometer 
having  a pressure  of  400  atmospheres ; anew  realization  on  a large  scale  of  Foucauld 
pendulum,  showing  the  rotation  of  the  earth,  the  deviation  toward  the  east  of  fall- 
ing bodies,  etc. 

It  will  be  an  observatory  and  a laboratory  such  as  has  never  before  been  placed  at 
the  disposal  of  savants,  who  from  the  beginning  have  encouraged  the  undertaking 
with  their  warmest  sympathies. 

My  wish  has  been  to  erect  a triumphal  arch  for  the  glory  of  science  and  the 
honor  of  French  industry,  as  striking  as  those  reared  to  military  conquerors  by 
former  generations ; and  to  express  in  a most  emphatic  manner  that  the  monument 
I raise  is  placed  under  the  invocation  of  science,  I have  inscribed  in  golden  letters 
under  the  great  frieze  of  the  first  story  and  in  the  place  of  honor  the  names  of  the 
great  savants  who  have  honored  France  for  the  last  century. 


830 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


Between  the  brackets  is  a frieze  on  which  are  inscribed  in  golden 
letters,  perfectly  legible  from  below,  the  names  of  the  men  who  have 
honored  French  science. 

On  the  Paris  side  : Petiet,  Daguerre,  Wurtz,  Perdonnet,  Delambre, 
Malers,  Breguet,  Polonceau,  Dumas,  Clapeyron,  Borda,  Founder, 
Bichat,  Sauvage,  Pelouse,  Carnot,  and  Lamd. 

Trocadero  side : Seguin,  Lalande,  Tresca,  Poncelet,  Bresse,  La- 
grange, Belanger,  Cuvier,  Laplace,  Dulong,  Chasles,  Lavoisier, 
Ampere,  Chevreuil,  Flacliat,  Xavier,  Legendre,  Chaptal. 

Crenelle  side;  Jamin,  Gay-Lussac,  Fizeau,  Schneider,  Le  Clnite- 
lier,  Bertliier,  Barruel,  de  Dion,  Gouin,  Jousselin,  Broca,  Becquerel, 
Coriolis,  Cail.  Triger,  Giffard,  Perrier,  and  Sturm. 

Towards  the  Ecole  Militaire : Cauchy,  Legrand,  Regnault,  Fres- 
nel. Prony,  Vicat,  Ebelmen,  Coulomb,  Poinsot.  Foucault,  Delaunay, 
Morin,  Hauy,  Combes,  Thenard,  Arago,  Poisson  and  Monge. 

Plate  XVIII  gives  a general  view  of  the  complete  structure. 

(301)  Statistics. — The  weight  of  the  iron  contained  in  the  tower  is 
about  7,300  tons.  The  weight  of  the  rivets  is  450  tons  and  their 
total  number  2,500,000.  Of  this  quantity  800,000  were  hand  driven 
on  the  tower  for  uniting  the  parts  already  prepared.  The  number 
of  metallic  pieces  is  12,000,  which,  on  account  of  their  varying  form 
and  position  in  space,  required  special  drawings. 

Forty  draftsmen  and  computers  worked  steadily  for  two  years  to 
complete  the  plans,  specifications  and  computations. 

It  took  ten  draftsmen  from  8 o’clock  in  the  morning  to  10  o’clock 
at  night  for  one  month  to  prepare  the  drawings  for  one  panel,  i.  e. 
10  meters  of  the  tower.  The  drawings  were  made  with  great  pre- 
cision up  to  the  ten-thousandth  of  a meter. 

The  plans  of  the  tower  comprised  500  drawings  and  2,500  working 
drawings  for  the  whole  27  panels.  Each  piece  of  which  the  tower 
was  built  was  designed,  shaped,  and  bored  at  the  works  at  Levallois- 
Perret  and  was  found  to  fit  exactly  into  its  place  when  it  reached 
the  Champ  de  Mars. 

From  150  to  200  men  were  employed,  at  the  rate  of  0.80  to  1 franc 
per  hour. 

(362)  Color. — The  tower  is  painted  a chocolate  color,  which  is  de- 
scribed as  a reddish  bronze,  from  the  foot  to  the  first  story;  from  the 
first  to  the  second  story  the  same  tint,  but  lighter;  from  the  second 
story  to  the  top  it  becomes  lighter  and  lighter  until  the  cupula  is 


almost  yellow. 

(363)  Cost. — 

Francs. 

Foundations,  masonry,  pedestal  . 900,000 

Erection,  metal,  city  duties  on  the  iron 3,800,000 

Painting,  four  coats 200,000 

Elevators  and  machines 1, 200, 000 

Restaurants,  decorations,  different  buildings 400. 000 


Total 6,500.000 


Paris  Exposition  of  1889— Vol.  3. 


Civil  Engineering,  etc.— PLATE  XVIII. 


COMPLETE  VIEW  OF  THE  EIFFEL  TOWER. 


CIVIL  ENGINEERING,  ETC. 


831 


(3G4)  The  Mont-yon  prize  in  mechanics. — The  F reach  Academy  of 
Sciences  has  just  awarded  the  Montyon  prize  of  mechanics  to  M.  G. 
Eiffel  as  a mark  of  their  appreciation  of  his  skill  in  the  erection  of 
iron  structures. 

(365)  Acknowledgment. — I wish  here  to  express  my  obligations  to 
MM.  Eiffel,  Salles,  and  Nouguier  for  numerous  courtesies  received, 
as  well  as  for  information,  printed  descriptions,  and  heliographs,  of 
which  liberal  use  has  been  made  in  this  report. 

Figures  231,  235  to  239,  inclusive,  are  from  copies  of  La  Nature, 
and  Figs.  233,  234,  240  to  242,  inclusive,  are  from  Xansouty's  book  on 
the  Eiffel  tower. 

Supplementary  note. — In  order  to  show  some  of  the  opposition  to 
M.  Eiffel's  scheme  for  a tower  300  meters  high  the  following  extract 
from  Engineering  is  appended  : 

On  the  5th  of  November,  1886,  the  finance  committee  of  the  Paris  Exhibition 
voted  a credit  of  1,500,000  francs  as  a subsidy  for  the  unique  and  monumental  work 
M.  Gustave  Eiffel  had  undertaken  to  construct,  and  which  was  to  be  one  of  the 
great  original  features  of  the  exhibition.  The  idea  of  erecting  a tower  1.000  feet 
in  height  was  received  with  a very  general  feeling  of  distrust  and  even  of  dismay ; 
not  that  anyone  doubted  the  capability  of  the  bold  and  successful  engineer  to  com- 
plete the  work  to  which  he  had  pledged  himself,  but  the  misgivings  were  very 
general  as  to  the  effect  that  such  a novel  construction  would  have  upon  the  archi- 
tectural features  of  the  Exhibition,  and  a widespread  cry  of  influential  voices  went 
up  from  Paris  as  a protest  against  the  engineering  outrage  that  was  to  be  inflicted 
upon  the  Frencii  metropolis.  It  is  rather  curious,  now  that  the  tower  is  completed 
and  the  great  consensus  of  public  opinion  is  loud  in  its  approval,  to  recall  the  re- 
monstrances addressed  to  M.  Alphand,  the  Director-General  of  Works,  against  the 
proposed  column.  “ We  wish — authors,  painters,  sculptors,  architects,  enthusiastic 
lovers  of  beauty — which  has  hitherto  been  respected  in  Paris — to  protest  with  all  our 
energy,  and  with  all  the  indignation  of  which  we  are  capable,  in  the  name  of  art 
and  of  French  history  now  menaced,  against  the  erection  in  the  heart  of  our  cap- 
ital of  the  useless  and  monstrous  Eiffel  tower,  which  public  satire,  often  full  of  good 
sense  and  a spirit  of  justice,  has  already  christened  the  Tower  of  Babel.  With- 
out falling  into  extravagance  we  claim  the  right  to  assert  that  Paris  stands  without 
a rival  in  the  world.  Above  its  streets  and  boulevards,  along  its  quays,  amidst  its 
magnificent  promenades,  abound  the  most  noble  monuments  which  human  genius 
has  ever  put  into  execution.  The  soul  of  France,  creator  of  chefs-d’oeuvre,  shines 
forth  from  this  wealth  of  stone.  Italy,  Germany,  Flanders,  so  justly  proud  of 
their  artistic  heritage,  possess  nothing  comparable,  and  from  all  corners  of  t lie  uni- 
verse Paris  commands  admiration.  Are  we.  then,  going  to  allow  this  to  be  pro- 
faned ? Is  the  city  of  Paris  to  permit  itself  to  lx*  deformed  by  monstrosities,  by  the 
mercantile  dreams  of  a maker  of  machinery;  to  be  disfigured  for  ever  and  to  be 
dishonored?  For  the  Eiffel  tower,  which  even  the  United  States  would  not  coun- 
tenance, is  surely  going  to  dishonor  Paris.  Everyone  feels  it.  everyone  says  so, 
everyone  is  plunged  into  the  deepest  grief  about  it.  and  our  voice  is  only  a feeble 
echo  of  universal  opinion  properly  alarmed. 

li  When  foreigners  will  come  to  visit  our  exhibition  they  will  cry  in  astonishment: 

‘ Is  this  horror  that  Frenchmen  have  invented'  intended  to  give  us  an  idea  of  the 
taste  of  which  they  are  so  proud?  And  they  will  be  right  to  mock  us,  because  the 
Paris  of  the  sublime  architects,  the  Paris  of  Jean  Goujon,  of  Germain  Pilon,  of 
Puget,  of  Rude,  of  Barye,  will  have  become  the  Paris  of  M.  Eiffel.  Nothing  further 


832 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


is  wanting  to  prove  the  justice  of  what  we  say  than  to  realize  for  an  instant  this 
tower  dominating  Paris,  like  a gigantic  and  black  factory  chimney,  crushing,  with 
its  barbarous  mass,  Notre  Dame,  the  Sainte  Chapelle,  the  Tour  St.  Jacques,  the 
Louvre,  the  dome  of  the  Invalides,  the  Arc  de  Triomphe  ; all  our  monuments  hu- 
miliated, all  our  architecture  shrunken,  and  disappearing  affrighted  in  this  bewild- 
ering dream.  And  during  twenty  years  we  shall  see,  stretching  over  the  entire 
city,  still  thrilling  with  the  genius  of  so  many  centuries,  we  shall  see  stretching  out 
like  a black  blot  the  odious  shadow  of  the  odious  column  built  up  of  riveted  iron 
plates.”  And  so  forth,  and  so  forth.  To  this  vehement  protest  were  attached  the 
names  of  many  of  the  best-known  men  of  France — Meissonier,  Gounod,  Gamier, 
Sardou,  Gerome,  Bonnat,  Bouguereau,  Dumas,  Copp6e,  etc.  But  these  well-meant 
ill-judged  remonstrances  were  not  heard,  and  to-day  the  Eiffel  tower  stands  com- 
pleted. the  marvel  of  the  exhibition  and  the  glory  of  the  constructor.  The  noble 
monuments  of  Paris  apparently  thrill  as  much  as  the}-  did  before  with  the  genius  of 
the  centuries,  and  the  grand  proportions  of  the  Arc  de  l'Etoile  do  not  seem  to  have 
suffered  because  a great  French  engineer  has  achieved  a triumph  of  construction. 
If  foieign  criticism  was  not  set  forth  in  such  brave  words  as  those  we  have  quoted 
above,  it  was  none  the  less  hostile ; but  foreign  criticism  is  generally  more  or  less 
colored  by  jealousy,  and  is  therefore  not  of  much  account. 

Chapter  XLYI. — The  Machinery  Hall. 

(36G)  The  enormous  machinery  hall  is  justly  considered  the  bold- 
est work  of  the  exhibition;  it  illustrates  the  extraordinary  progress 
of  engineering,  and  its  new  lessons  in  the  art  of  construction  are 
already  beginning  to  be  applied. 

(3G7)  The  Osiris  prize. — A committee  of  French  journalists  to 
whom  was  assigned  the  task  of  awarding  the  Osiris  prize  of  100,000 
francs  to  the  most  important  work  of  the  exhibition,  after  having 
paid  a just  tribute  to  the  palaces  of  the  fine  and  of  the  liberal  arts, 
constructed  by  M.  Formigfi,  and  to  the  central  dome  by  M.  Bouvard, 
decided  to  give  it  to  the  constructors  of  the  machinery  hall.  M. 
Dutert,  the  architect  who  conceived  the  idea,  prepared  the  plans,  and 
superintended  the  erection,  received  20,000  francs;  M.  Contamin, 
who  prescribed  the  dimensions  and  calculated  the  strength  of  all  the 
ironwork,  15,000  francs ; to  the  five  assistant  architects  and  engi- 
neers, 3,000  francs  each;  the  other  50,000  francs  were  distributed 
among  the  workmen. 

(3GS)  History. — In  1878  M.  de  Dion  made  a bold  beginning  by  con- 
structing the  gallery  of  machines  with  a single  iron  arch  without  a 
tie-rod,  the  trusses  forming  one  solid  piece  with  the  piers,  and  built 
into  the  masonry;  but  these  trusses  were  of  only  30  meters  span, 
and  the  height  did  not  exceed  25  meters. 

In  the  railroad  station  at  St.  Pancreas,  in  London,  the  trusses 
have  in  appearance  no  intermediate  point  of  support;  in  reality 
the  ends  are  united  by  tie-rods  concealed  beneath  the  flooring;  the 
span  is  only  73  meters. 

In  1889  the  system  adopted  had  already  been  employed  by  Oudry 
in  the  construction  of  the  swinging  bridge  at  Brest,  for  a few  iron 


CIVIL  ENGINEERING,  ETC.  833 

viaducts,  and  in  some  railroad  stations  in  Germany,  but  it  had 
never  before  been  applied  on  so  gigantic  a scale. 

Before  entering  upon  a detailed  description  of  the  construction 
and  erection  of  this  remarkable  building  it  may  not  be  out  of  place 
to  show  by  the  following  extract  from  one  of  the  Paris  journals,* 
what  impression  the  sight  of  this  vast  edifice  produced  upon  the- 
enlightened  public. 

If  the  Eiffel  tower  was  an  unexpected  surprise,  a triumph  of  originality  and  of 
daring  skill,  the  machinery  hall  was  found  lo  be  only  one  degree  less  marvelous; 
and  this  because  the  progress  of  modern  architecture  and  of  the  science  of  engineer- 
ing had.  from  one  decade  to  another,  led  us  up  to  this  superb  realization  of  the  un- 
explored possibilities  of  both.  Never  before,  in  the  opinion  of  engineers  of  all 
countries  who  have  visited  it,  has  a building,  proportionately  to  its  vast  dimensions, 
been  constructed  with  such  a wondrous  combination  of  solidity,  lightness,  amt 
grace,  the  general  effect  being  enhanced  by  the  flood  of  light  freely  admitted 
to  all  parts  of  the  palace.  The  Government  is  therefore  to  be  most  heartily'  con- 
gratulated, on  national  and  artistic  grounds  alike,  upon  the  initiative  which  it  has 
taken  to  permanently  preserve  this  magnificent  building,  together  with  those  set 
apart  to  the  fine  and  liberal  arts,  in  addition  to  the  grand  central  dome. 

The  machinery  hall  is,  indeed,  the  most  prodigious  outgrowth  of  the  joint  ingenuity 
and  skill  of  architect  and  engineer.  To  bring  under  one  roof  all  the  machinery 
that  was  to  be  exhibited  was  a problem  which  almost  defied  solution.  The  task, 
however,  was  happily  surmounted  by  the  cooperation  of  M.  Dutert,  the  eminent 
architect,  and  MM.  Contamir,  Charton,  and  Pierron,  engineers.  M.  Dutert.  who 
conceived  the  entire  plan  of  the  work,  tracing  it  out  even  to  its  minutest  features, 
superintended  tne  decorative  details.  Taking  up  this  vast  conception  of  an  artist, 
M.  Contamin  stamped  upon  it  the  hall-mark  of  science  by  calculating  the  efforts  of 
the  materials,  estimating  their  resistance,  and  insuring  the  due  solidity'  and  equi- 
librium of  the  whole  structure.  He  it  was  who  superintended  the  operation  of 
fitting  together  the  ribs  and  girders  and  general  framework  resting  upon  the  solid 
squares  of  masonry  constituting  the  foundations.  The  palace  is  420  meters  in 
length,  and  115  in  width,  covering  a superficial  area  of  48,335  square  meters,  or 
about  114  English  acres. f It  is  estimated,  indeed,  that  should  the  building  be  ulti- 
mately converted  into  a military  riding  school,  it  will  afford  ample  space  for  exercis- 
ing 1 ,200  horses  at  a time.  Some  further  idea  of  its  commanding  proportions  may  be 
conveyed  by  the  statement  that  the  Vendome  column,  with  its  well-known  statue 
of  Napoleon  I,  might  easily  be  erected  within  the  four  walls,  as  it  would  leave  7 
meters  to  spare  between  the  head  of  the  figure  and  the  apex  of  the  arched  roof ; 
that  the  span  of  the  girders  supporting  this  roof,  which  is  48  meters  in  height, 
would  shelter  the  Arc  de  Triomphe;  and  that  the  nave  of  the  Palais  de  l’lndustrie 
is  only  half  the  length  and  half  the  width  of  that  of  the  Palais  des  Machines.  There 
is  sufficient  “free  play”  at  the  top  of  the  arching  girders  to  allow  of  the  slight 
displacement  that  takes  place  under  the  action  of  heat  and  cold.  The  only  points 
of  support  are,  in  fact,  at  the  base  of  the  girders  and  where  these  latter  meet  each 
other  in  the  center  of  the  roof:  but  these  chief  ribs,  be  it  noted,  are  connected  by 
longitudinal  girders,  the  whole  framework  being  otherwise  strengthened,  on  each 
side  of  the  building,  on  the  most  approved  principles.  The  method  which  was  fol- 
lowed enabled  the  constructors  to  carry  out  their  plans  with  the  minimum  of  mate- 
rials commensurate  with  necessary  strength  and  artistic  effect:  and  the  entire  cost 
of  the  palace  (7,514,095  francs,  of  which  5.398,307  francs  was  for  ironwork  alone) 

*Galignani's  Messenger,  July,  1889. 

t The  nave  alone,  not  including  the  lateral  galleries. 

H.  Ex.  410— VOL  III 53 


834 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


was  correspondingly  lessened.  Over  the  summit  of  the  roof  is  a narrow  gallery 
for  workmen. 

Each  of  the  arched  girders  running  up  the  sides  of  the  building  consists  of  two 
ribs,  an  inner  and  outer  one,  solidly  bound  together,  above  and  below,  crosswise, 
one  regular  square  alternating  with  an  elongated  one,  the  only  real  point  of  sup- 
port being,  as  we  have  said,  in  the  masonry  at  the  base,  inasmuch  as  the  girders 
meet  each  other  lightly,  with  a sort  of  elastic  touch  at  the  apex  above.  The  total 
weight  of  material  over  the  grand  nave  is  only  7,400  tons,  a little  more  than  the 
mass  of  iron  used  in  the  construction  of  the  Eiffel  tower.  On  either  side  of  the  ma- 
chinery hall  is  a gallery  15  meters  in  width,  to  which  access  is  obtained  by  broad 
staircases,  as  also  by  lifts.  One  point  deserving  special  mention  is  that  the  contract 
for  the  building  was  divided  between  two  firms.  One-half  of  the  palace,  that  on 
the  Avenue  de  Labourdonnais  side,  was  constructed  by  the  Compagnie  Fives-Lille, 
and  the  other  half,  stretching  to  the  Avenue  de  Suffren,  by  the  Societe  Cail.  The 
former  company  put  its  girders  into  position  in  heavy  sections,  some  of  these  weigh- 
ing 48  tons  apiece,  whilst  those  of  the  other  contractors  were  set  up  in  fragments 
of  3 tons.  Had  steel  been  used,  the  framework  would  have  been  much  lighter 
than  it  is,  but  the  idea  of  resorting  to  it  was  abandoned  on  the  two-fold  ground 
of  expense  and  the  necessity  of  hastening  the  execution  of  the  work.  Those  who 
believed  that  iron  was  ill  adapted  to  the  requirements  of  art  as  applied  to  industry 
have  been  agreeably  surprised  by  the  happy  results  achieved  by  M.  Dutert  and 
the  engineers  who  so  ably  cooperated  with  him  in  this  veritable  palace  of  wonders. 

The  internal  decorations,  under  the  glass  roof  arching  downwards  toward  the 
sides,  are  most  effective,  the  chief  tone  being  of  a rosy  yellow  giving  rise  to  some 
curious  effects  of  the  sun's  rays.  Thus,  toward  evening,  all  the  panes  over  the 
right  side  of  the  nave  assume  a rosy  tint,  whilst  those  opposite  are  of  a light-green 
hue,  the  contrast  suggesting  that  between  rubies  and  emeralds.  Ten  large  panels 
and  one  hundred  and  twenty-four  smaller  ones  have  been  painted  by  MM.  Alfred 
Rube,  Philippe  Chaperon,  and  Marcel  Jambon ; the  former  represehting  the  arms 
and  commercial  or  other  attributes  of  the  leading  capitals  of  the  world  (Berlin,  of 
course,  excepted),  and  the  latter  the  escutcheons,  etc.,  of  the  minor  cities  and 
towns,  including  all  the  chefs-lieux  of  French  departments.  Over  the  chief  en- 
trance in  the  Avenue  de  La  Bourdonnais,  is  a large  rose  window  in  different  colors. 
The  ornamentations  on  the  outside  are  exceedingly  striking.  The  vast  arch  over 
the  porch  is  decorated  with  a foliated  design  showing  between  the  leaves  various 
implements  of  labor.  On  the  lintel  is  the  inscription  “Palais  des  Machines,”  in 
decorative  faience,  the  groundwork  being  an  olive  branch.  This  is  supported 
by  two  groups  10  meters  in  height.*  The  first,  by  M.  Barrias.  represents  electricity, 
and  is  composed  of  two  female  figures.  One  of  these,  bv  a finger  touch,  sends  an 
electric  flash  through  the  globe,  whilst  the  other,  resting  in  a recumbent  position 
on  a cloud,  stretches  forth  her  band  to  her  companion:  they  symbolize  the  two 
opposite  currents.  The  second  group,  by  M.  Chapu,  shows  a female  figure  personi- 
fying steam,  and  a workman  clasping  her  in  his  arms.  A colored  window  above 
sets  forth  the  arms  of  the  various  powers  taking  part  in  the  exhibition.  In  the  center 
of  the  gable  at  the  opposite  end  are  some  colored  panes  depicting  the  battle  of  Bou- 
vines.f  and  facing  the  Ecole  Militaire  is  a window  dedicated  to  the  “Chariot  of  the 
Sun.” 

Those  who  enter  the  machinery  hall  from  the  general  industries  gallery  pass 
through  a central  vestibule  which  from  its  rich  decoration,  may  be  regarded  as  a 
sort  of  salon  d'honneur.  Here  is  a handsome  cupola  covered  with  colored  panes  and 
mosaics,  the  former  showing  the  leading  agricultural  products  of  the  country,  such 
as  flax,  hemp,  wheat,  and  maize.  The  painted  pendentives  represent  the  arts, 


See  Plates  XXI  and  XXII. 


f Plate  XX. 


CIVIL  ENGINEERING,  ETC. 


835 


sciences,  letters,  and  commerce.  The  numerous  other  allegorical  subjects  ornament- 
ing the  vestibule  have  been  greatly  admired.  At  the  foot  of  the  handsome  stair- 
case leading  to  the  gallery  are  two  splendid  bronze  figures,  each  bearing  a cluster 
of  twenty  incandescent  lamps. 

Such,  in  brief,  is  the  general  outline  of  the  building  itself.  It  may  be  urged  that 
the  Palais  des  Machines  affords  evidence  that  a fresh  era  in  architecture  has  been 
inaugurated,  that  ceci  tuera  cela,  and  that  the  age  of  stone  is  to  be  succeeded  by 
the  age  of  iron.  We  do  not  think  so.  It  is  true  that  the  engineers  are  just  now 
triumphant  in  many  directions.  The  chief  of  the  state  is  an  engineer;  an  engineer, 
M.  (le  Freycinet,  is  minister  of  war;  M.  Alphand,  another  engineer,  was  one  of  the 
organizing  directors  of  the  Universal  Exhibition;  and  the  name  of  the  engineer, 
Eiffel,  has  become  something  more  than  a household  word.  With  respect  to  the 
architectural  question,  however,  it  is  evident  that  engineers  can  dictate  to  archi- 
tects only  in  the  case  of  immense  buildings  whose  distinctive  characters  is,  after 
all,  that  of  use  rather  than  ornament.  Those,  however,  who  look  at  the  interior 
of  this  machinery  hall  for  the  first  time  can  not  form  an  estimate  of  its  imposing 
dimensions;  its  architectural  lines  do  not  draw  the  attention  upwards,  and  so  its 
roof  appears  lower  than  that  of  the  smallest  Gothic  cathedral.  Nobody,  at  a glance, 
would  imagine  that  he  stood  in  the  highest  covered  building  in  the  world. 

The  motive  power  is  distributed  by  means  of  four  shafts  extending  from  one  end 
of  the  building  to  the  other,  the  total  force  actually  at  work  being  equal  to  2,600 
horse  power,  although  5,640  horse  power  may  be  developed  if  necessary.  This  is 
more  than  double  the  power  placed  at  the  disposal  of  exhibitors  in  1878.  In  1855 
the  figure  stood  at  350  and  in  1867  at  638.  There  has,  therefore,  been  a remarkable 
progression.  Visitors  may  watch  the  machinery  in  movement  from  two  traveling 
cranes,  or  pouts  roulants,  as  they  are  more  correctly  described  in  French,  which 
move  to  and  fro  on  rails  at  some  height  above  the  shafts.  The  bird's-eye  view  thus 
obtained  proved  so  startling  to  an  Annamite  the  other  day  that  he  turned  suddenly 
pale,  or  pale  yellow,  on  glancing  down  at  the  iron  monsters  which  to  his  untutored 
and  superstitious  gaze  seemed  to  be  harboring  destructive  designs  upon  the  passing 
crowds,  and  he  looked  as  though  he  were  ready  at  a moment’s  notice  to  prostrate 
himself  at  the  feet  of  some  modern  Moloch!  The  steam  boilers  occupy  a place  in  a 
covered  court  facing  the  Avenue  de  Lamotte-Piquet,  and  it  should  here  be  stated 
that  the  machinery  on  the  Quai  d’Orsay  is  set  in  motion  by  the  engines  in  the  ma- 
chinery hall,  a motor  turning  a dynamo  for  the  transmission  of  electricity  to  the 
agricultural  hall.  Most  of  the  engines  exhibited  in  the  Palais  des  Machines  belong 
to  the  Corliss.  Sulzer.  and  Wheelock  systems,  and  are  generally  of  the  compound 
type,  but  others  will  also  be  studied  with  interest  by  technical  judges. 

The  general  arrangement  of  the  exhibits  may  lx*  described  in  a few  words.  As 
the  visitor  passes  through  the  palace  from  the  Avenue  de  Suffren  to  the  Avenue  de 
Labourdonnais,  he  finds  that  the  first  half  on  his  right  is  devoted  to  those  relating 
to  civil  engineering,  the  ceramic  arts,  cabinet-making,  mechanism  of  various  kinds, 
electricity,  agriculture,  mining,  and  metallurgy,  printing,  and  paper-making;  and 
the  other  half,  on  the  left,  to  railway  material,  and  spinning,  weaving,  and  iron 
working  machinery,  etc.,  and  the  special  places  set  apart  to  Switzerland,  Belgium, 
the  United  States,  and  England.  Between  the  machinery  ball  and  the  general  in- 
dustries gallery  is  a court  in  which  electrical  apparatus  of  all  kinds  may  be  seen  in 
full  working  order  at  night.  It  constitutes  one  of  the  most  novel  and  attractive 
features  of  the  exhibition.  The  focus  of  one  great  lamp  consists  of  a cluster  of 
15,000  small  incandescent  lights. 

(3G9)  Extract  f rom  the  official  specifications. — The  following  ex- 
tract from  the  official  specifications  will  give  an  idea  of  the  great 
pressures  which  the  foundations  were  required  to  sustain. 


836 


UNIVERSAL  EXPOSITION  OE  1889  AT  PARIS. 


The  great  nave  consists  of  nineteen  bays,  varying  in  length  as  follows:  Two  at  the 
end.  of  25.295  meters  each;  sixteen  intermediate,  of  21.50  meters,  and  one  in  the 
middle,  of  26.40  meters.  There  are  twenty  principal  girders  (Fig.  247),  the  two  end 
ones  being  heavier  than  the  others.  These  principal  girders  are  connected  at  the 
top  by  two  ridge  purlins,  with  a walk  and  parapet  above  them,  and  on  the  sides 
by  eight  lattice  purlins,  and  two  plate  purlins  at  the  right  of  the  main  gutters. 
Between  the  principal  girders  each  bay  is  divided  into  four  parts  by  three  girders 
at  right  angles  to  the  purlins,  to  which  they  are  attached.  These  latter  hold  the 
minor  purlins  and  sash  bars,  with  the  iron  framing  for  the  roof  covering.  Later- 
ally, the  principal  girders  are  connected  by  lattice  girders  at  the  first  floor  level  of 
the  side  galleries,  and  under  the  gutter  by  lattice  arches  and  open  iron  work.  The 
weight  of  the  nave  was  estimated  at  7,709,100  kilograms,  and  the  thrust  of  each 
principal  girder  amounted  to  1 15,000  kilograms,  including  a weight  of  snow  and 
the  effect  of  a strong  wind  blowing  at  the  rate  of  40  meters  per  second. 

(370)  Foundations. — The  foundations  for  the  Machinery  Hall  were 
begun  on  the  5th  of  July,  1887,  and  were  finished  on  the  21st  of 
December.  The  structure,  according  to  the  specifications  just  given, 
consists  of  an  immense  nave  110  meters  wide  and  420  long,  with 
two  side  galleries  15  meters  wide,  containing  a single  story  8 meters 
above  the  ground,  with  grand  stands  at  each  end,  supported  on  iron 
pillars.  Access  to  this  story  is  obtained  by  four  great  staircases. 

The  twenty  great  curved  girders  of  110  meters  span  form  the 
framework  of  the  building;  they  are  jointed  at  the  top  and  at  the 
springing  lines.  The  axles  on  which  they  rest  are  on  a level  with 
the  ground.  The  bed  plates  or  cast-iron  bearings,  which  take  up  the 
thrust  of  the  arch  and  transmit  it  to  the  masonry,  had  to  be  made 
strong  enough  to  support  a vertical  load  of  412  tons,  and  a horizontal 
thrust  of  1 15  tons. 

As  provision  had  to  be  made  for  a system  of  underground  pipes 
for  water,  steam,  drainage,  etc.,  it  was  impossible  to  use  under- 
ground tie-rods  ; it  was,  therefore,  absolutely  necessary  to  make  the 
foundations  of  the  piers  or  abutments  of  the  great  girders  strong 
and  deep  enough  to  assure  the  perfect  security  of  the  edifice.  The 
twenty  great  girders  rest  on  forty  masonry  piers  entirely  hidden  in 
the  ground ; they  are  designated  by  the  letters  A,  B,  C,  etc.  (Fig. 
243). 

(371)  The  nature  of  the  soil  is  suitable  for  foundations,  where  it 
has  not  been  previously  disturbed,  but  unfortunately  for  the  present 
occasion,  the  Champ  de  Mars  has,  during  the  last  century,  been  the 
site  of  exhibitions  beginning  with  that  of  1780  and  ending  with  the 
recent  one  of  1878,  when  a deep  deposit  of  sand  was  removed  and 
replaced  with  rubbish. 

On  this  old  gravel  pit  a portion  of  the  foundation  had  to  be  made 
(this  portion  is  shaded  in  the  figure). 

Numerous  borings  had  shown  the  strata  (Fig.  244)  to  be  as  follows: 
made  ground  and  gravel,  for  a depth  of  7.50  meters;  plastic  clay, 
7.50  meters  ; quartz  sand,  1.50  meters  ; plastic  clay,  3. 10  meters  ; clay, 
5.40  meters;  marl,  19.40  meters  to  the  chalk. 


Fiq.  243.— General  plan  of  the  foundations  of  machinery  hall. 


837 


CIVIL  ENGINEERING,  ETC. 


; *.  ^ c 


-i-.u 


838 


UNIVERSAL  EXPOSITION  OF  1880  AT  PARIS. 


Made  ground. 


Plastic  clay. 

Quartz  sand. 
Plastic  clay. 
Hard  clay. 

Marl. 


US  et  I 


On  account  of  the  differences  in  the  strata  it  was  found  necessary 
to  adopt  three  types  of  piers  according  to  the  thickness  of  the  gravel 
on  which  they  rested.  Whenever  the  thickness  of  the  alluvial  de- 
posit exceeded  3 meters,  the  founda- 
tion of  the  pier  consisted  of  a block  of 
masonry  7 meters  long,  3. 50  wide,  and 
3.70  thick,  resting  on  a layer  of  bdton 
from  0.50  to  0.80  meter  thick.  (In 
this  first  case  the  resistance  of  the 
ground  was  required  to  he  3 kilo- 
grams per  square  centimeter).  This 
is  the  general  type  of  foundation, 
twenty-five  piers  out  of  forty  being  so 
constructed.  When  the  bed  of  gravel 
chalk.  rvrtmwi.mryym*  was  reduced  in  thickness,  without  fall- 

fig.  2«. -Geological  section.  ing  below  1.50  meters,  the  depth  and 

surface  of  the  bdton  was  considerably  augmented,  the  dimensions  be- 
ing 1.35  meters  in  thickness,  with  a surface  of  11.20  by  0.50  meters  in 
some  instances,  supporting  a mass  of  masonry  which  was  the  same 
for  all  the  piers;  the  resistance  in  this  latter  case  was  1.0  kilograms. 
Only  five  piers  were  constructed  on  this  type,  viz,  G,  M,  P,  Q.  and  P . 

Finally,  for  the  piers  which  had  to  be  constructed  on  the  site  of 
the  gravel  pit,  the  bed  of  beton  was  the  same  as  in  the  last  case,  but, 
before  laying  this,  a group  of  piles  0.33  meter  in  diameter  and  !) 
meters  long  was  driven  into  the  bed  of  quartz  sand,  which  extends 
below  the  layer  of  clay  7 meters  thick. 

The  foundations  on  the  line  A T began  on  July  5 and  presented  no 
difficulty,  but  in  sinking  the  piers  G P portions  of  the  foundations 
of  the  exhibitions  of  1878  were  met  and  blasted  out.  Figs.  245  and 
246  show  a vertical  section  and  plan  of  one  of  these  piers.  Each 
of  these  elliptic  excavations  was  20  by  15  meters  at  the  top,  11.20 
by  6.50  meters  at  the  bottom,  and  from  7 to  7.50  meters  deep.  The 
contents  varied  from  1.100  to  1,200  cubic  meters.  The  piles  were 
sawn  off  and  covered  with  a layer  of  bdton,  11.20  by  6.50  by  1.80 
meters,  amounting  to  131  cubic  meters.  The  operation  of  running 
in  and  ramming  the  bdton  occupied  26  men  two  days.  Upon  this 
the  various  layers  of  masonry  (Fig.  245)  were  built — varying  from 
120  to  130  cubic  meters — by  six  or  seven  masons  and  as  many  helpers, 
in  8 or  9 days. 

The  feet  of  the  principal  girders  were  at  the  reference  35.12  me- 
ters.* 

The  masonry  was  stopped  at  32.96  meters  to  put  in  the  anchor 
bolts  holding  the  bearings.  These  bolts  are  six  in  number,  united 
by  a network  of  T irons  imbedded  in  the  masonry. 


* Above  the  level  of  the  sea. 


CIVIL  -ENGINEERING,  ETC. 


839 


Fig.  345.— Foundation  of  a truss  girder;  elevation. 


Each  bolt  is  separated  from  the  masonry  by  being  placed  in  a cast- 
iron  tube,  which  allows  it  0.03  meter  play  in  every  direction.  At 


840 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


0.50  meter  above  the  reference  32.96  meters  each  cast-iron  tube  is 
prolonged  by  one  of  sandstone,  so  that  it  may  be  cut  to  the  exact 
height  of  the  bearing.  The  bearing  rests  upon  a large  cast-iron 
bed-plate,  so  that  rubblework  under  it  answers  very  well. 

The  foundations  were  completed  on  December  21  by  MM.  Manoury, 
Grouselle  & Co.,  contractors. 

(372)  Principal  girders  or  arched  ribs. — Each  principal  girder  is 
jointed  at  three  points,  i.  e.  at  the  top,  and  at  the  springing  lines  (Fig. 
247).  This  arrangement  simplifies  the  calculation  by  determining 
the  exact  points  of  application  of  the  stresses ; it  also  facilitates  the 
movements  due  to  the  variations  of  temperature,  which  cause  the 
ridge  to  rise  or  fall  as  the  girders  expand  or  contract. 

We  will  first  consider  the  arch  and  afterwards  the  spandrel,  which 
does  not  affect  its  strength,  but  simply  constitutes  a filling.  The 
arch  is  divided  into  twenty-four  panels  of  different  sizes.  The  dis- 
tance between  the  extreme  plates  of  the  intrados  and  extrados  at  the 
bottom  is  3.70  meters.  This  distance  continues  up  to  purlin  No.  5, 
whence  it  begins  gradually  to  diminish  to  nearly  3 meters  at  the 
top.  This  very  economical  form  gives  a character  of  lightness  and 
elegance  to  the  whole  girder. 

As  the  Figs.  248-254  indicate,  the  girder  consists  of  two  webs  450 
by  9 millimeters  for  the  part  between  panels  Nos.  1 to  16;  450  by  10 
for  that  between  panels  16  and  21,  and  450  by  23  for  that  between 
21  and  24.  (Dimensions  given  in  millimeters). 

These  webs  are  united  by  plates  770  by  8 for  the  extrados,  and  900 

by  10  for  the  intrados,  and  four  angle  irons 


The  uprights  and  diagonals  are  fastened  to  the  two  webs. 

For  the  part  between  purlin  No.  4 and  the  joint  at  the  foot  of 
the  girder  the  stresses  are  considerable,  and  the  sections  have  been 
strengthened. 

The  covering  plates  for  those  parts  subject  to  the  greatest  stress 
are  six  in  number.  A plate  of  10  thick  extends  over  the  entire  gir- 
der, a plate  of  13  over  a shorter  length,  one  plate  of  11  over  a certain 
length  of  the  intrados,  also  two  of  12,  and  one  of  13,  which  makes 
a total  of  71  millimeters.  (See  Fig.  249). 

At  the  extrados,  the  last  two  plates  are  omitted,  and  they  have 

been  replaced  by  two  angle  irons  which  connect  the 

spandrel  with  the  principal  girder.  (Fig.  252). 

The  portion  of  the  arch  between  two  purlins  is  formed  by  three 
small  diagonals  and  two  large  ones.  This  division  of  the  diagonals 
into  small  and  large  serves  to  decorate  the  arch,  and  has  also  the 
advantage  of  giving  the  same  distance,  10.72  meters,  between  the 
vertical  purlins,  which  is  indispensable  considering  their  great 
height. 


23  S2S 


H.  Ex.  410 — vol.  hi — To  face  page  840. 


Fig.  247.— One  of  the  principal  tru; 


i ns  irdcrs  of  machinery  hall. 


■CIVIL  ENGINEERING,  ETC, 


841 


Sections  of  the  great  truss  girders. 


Fig.  24?. 


Fig.  251. 


842 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


Sections  of  the  great  trcss  girders. 


Fig.  253. 


(373)  The  diagonals  are  formed  by  T -irons  of  different  dimen- 
sions, according  to  their  position  in  the  section  with  respect  to  the 
webs  of  450.  From  the  panel  21  to  12  the  diagonals  areT-h*ons 
200  by  100 
14 


In  the  panels  22,  23,  24  they  are  T-irons  14 


strengthened  by  a plate  200  by  10;  in  the  panels  11  to  1 they  are 
170  by  90 
13 


CIVIL  ENGINEERING,  ETC. 


843 


The  panels  at  the  head  and  foot  are  of  an  entirely  different  con- 
struction. In  those  of  the  head,  which  have  to  resist  a horizontal 
thrust  of  74,950  kilograms  under  ordinary  circumstances,  of  114,300 
when  the  roof  is  covered  with  snow,  and  of  119,840  in  case  of  a wind 
having  a mean  velocity  of  40  meters  per  second,  two  large  diagonal 
double  T -irons  are  used,  which  take  the  thrust,  and  form,  with  a 
series  of  supplementary  webs  and  strengthening  plates,  a very  stiff 
frame. 

Figs.  204  and  205  show  the  method  of  attaching  the  bearings  to 
the  web  of  the  arch. 

The  bottom  panel  is  entirely  plain  and  has  two  webs  strengthened 
by  several  supplementary  plates. 

The  panel  rests  on  the  upper  bearing  by  means  of  an  additional 
plate  20  millimeters  thick,  to  which  it  is  fastened  by  four  bolts.  The 
lower  pillow  block  rests  on  a cast-iron  plate,  to  which  it  is  attached 
by  long  anchor-bolts  imbedded  in  masonry,  as  has  been  previously 
described. 

For  facility  of  transportation  the  different  sections  were  5 or  0 
meters  in  length,  the  joints  being  made  in  the  middle  of  a panel,  and 
care  taken  that  the  angle  irons  should  break  joint. 

(374)  The  spandrel  has  the  same  construction  as  the  arch  itself. 

It  is  formed  of  two  webs  400  by  9 united  by  a plate  770  by  8,  and 

f i • 100  by  100 

tour  angle  irons  •- . 

The  uprights  are  in  the  prolongations  of  those  of  the  arch,  and  like 
them  placed  beneath  the  two  webs.  The  vertical  part  of  the  span- 
drel outside  of  the  girder,  which  carries  the  arches  of  the  lateral 
galleries,  and  the  gutter  purlins,  is  strengthened  by  two  webs  150  by 

„ i e , . 100  by  100 

7 and  four  angle  irons . 

The  joints  between  the  gutter  purlins  and  the  girder  are  made  by 
bolts,  on  account  of  the  difficulty  of  riveting  at  this  height,  and  the 
gutter  is  secured  to  the  uprights  of  this  purlin  by  a number  of 
brackets.  All  the  space  below  this  purlin  above  the  arches  of  the 
lateral  galleries  is  closed  by  a plate-iron  curtain  4 millimeters  thick 
formed  by  plates  1.73  meters  long  and  lapping  over  each  other  for  a 
distance  of  0.150  meter. 

(375)  Purlins. — There  are  twelve  purlins,  including  those  which 
support  the  gutters,  which  are  differently  constructed  from  the  others. 
The  two  latter  are  formed  of  a web  1.05  meters  high  by  8 millimeters 
thick,  and  two  plates  300  by  9 millimeters  with  four  angle  irons 
70  by  70 

7 

The  uprights,  consisting  of  a web  and  four  angle  irons,  stiffen  the 
beam,  and  serve  at  the  same  time  as  a support  for  the  rafters  on  the 
interior  and  for  the  gutter  corbels  on  the  exterior. 


844 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


The  other  ten  purlins  (Figs.  255-257)  are  each  formed  of  an  |\J- 
shaped  lattice  girder.  The  tension  bars  are  two  flat  irons  120  by  8 
joined  on  each  side  to  the  two  plate  webs  of  350  millimeters  thick. 
For  the  two  panels  near  the  trusses  where  the  shearing  stress  is 
greatest  the  thickness  of  the  plates  is  0 millimeters. 


The  purlins  have  been  calculated  by  considering  them  as  pieces 
resting  on  two  supports  and  carrying  three  separate  loads,  viz,  the 
rafters,  a portion  of  sashes  and  glass,  and  their  own  weight.  These 
conditions  give  a height  in  the  middle  of  the  purlin  of  1.80  meters, 
and  this  height  has  been  augmented  toward  each  end  for  architec* 
tural  effect. 

(370)  Rafters. — The  purlins  are  braced  by  a series  of  rafters  run- 
ning from  the  ridge  to  the  gutters  (Figs.  258-262).  Upon  the  rafters 
rest  the  minor  purlins  which  support  sash  bars.  Rafters  Nos.  1 and 
2 have  been  selected  as  illustrations  on  account  of  the  peculiar  ar- 
rangement at  their  upper  parts  due  to  the  joining  of  the  principal 
girders. 

On  account  of  the  great  length  of  the  purlins  it  is  indispensible 
that  they  should  be  braced  at  several  points;  this  is  accomplished  by 


CIVIL  ENGINEERING,  ETC. 


845 


Machinery  haij-  Rafter. 


SECTION  ' C-D 
sc*i£  fa' 


Figs.  258-261.  Rafter,  rafter  end,  and  sections  A B and  C D. 


846 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


means  of  the  three  rafters  placed  between  two  principal  girders. 
This  bracing  is  made  secure  by  putting  at  the  right  of  each  rafter 
and  for  each  purlin  a large  ear  of  plate  and  angle  irons.  Between 
the  two  ears  a sheet  of  lead  15  millimeters  thick  is  placed. 

This  arrangement  does  not  prevent  the  movements  due  to  varia- 
tions of  temperature,  for  when  the  girder  expands  the  ridge  rises. 
The  lead  gives  at  its  lower  part  and  allows  the  motion. 

Six  bolts  are  used  to  unite  the  two  cars,  but,  in  order  to  leave  a 
slight  play,  care  is  taken  not  to  screw  up  the  nuts  too  tightly. 

The  two  ridge  purlins  support  a walking  gallery  with  an  outside 
parapet.  This  gallery  is  fixed  to  the  right  gutter  purlin  only,  and  is 
free  from  the  other  so  as  to  vary  its  position  as  the  roof  moves. 

(37?)  Erection. — The  contracts  for  iron  work  and  the  erection  of 
the  Machinery  Hall  were  allotted  to  three  companies,  viz,  the  gables 
and  lateral  galleries  to  MM.  Baudet,  Donon  & Co.,  and  the  other 
portions  of  the  great  nave  were  equally  divided  between  the  com- 
panies Fives-Lille  and  Caile. 

(378)  The  method  adopted  by  Fives-Lille  Co.  is  due  to  M.  Lantrac, 
chief  engineer  of  the  company,  and  was  superintended  by  M.  Balme, 


the  resident  engineer.  This  system  consisted  in  putting  the  parts  of 
the  girder  together  on  the  ground  so  as  to  form  four  sections,  viz, 
two  piers  and  two  arches,  then  raising  these  four  sections  to  their 
proper  places,  and  riveting  them  together  on  scaffoldings  arranged 
for  the  purpose. 

The  scaffoldings  required  for  the  whole  operation  were  three  in 
number,  one  high  central  one,  and  two  lateral  ones;  they  are  shown 
in  Fig.  263;  they  are  mounted  on  wheels,  and  are  entirely  inde- 
pendent of  each  other. 

Description  of  Fir,.  263. 

Fig.  203  represents  the  method  of  raising  the  girders,  with  the  traveling  scaffold- 
ings in  use. 


I 


CIVIL  ENGINEERING,  ETC.  847 

Machinery  Hall.  Erection  op  a great  truss  girder.  Method  adopted  by  the  Fvies-Lillf. 

Company. 


\/ 

¥ 

y 

\\5 

X 

X 

Fig.  2S3.— Elevation  and  plan  of  girders  and  scaffolding. 


848 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


I I',  piers;  X,  high  central  scaffoldings  22  meters  long,  19  meters  wide-, 
-14  meters  high,  running  on  18  wheels  0.80  meter  in  diameter  ; Y Z,  two  smaller 
traveling  scaffoldings  just  alike  ; U'  U1,  secondary  scaffoldings  fastened  to  Y 
and  Z ; V'  V',  traveling  scaffoldings  fastened  on  to  Y and  Z ; a,  a,  firmly  braced 
projecting  stage ; b,  c,  hoisting  pulleys  on  a ; d,  e,  winches  for  b and  c ; f,  g, 
smaller  winches  below;  h,  i,  small  cranes  ; j,  lifting  pulley;  k,  l,  winches  ; in,  ]>, 
foot  of  girder  ; x,  a platform  on  piles,  with  a winch  ; n,  the  rest  of  the  half  gir- 
der; r,  guys;  w,  pulleys;  y,  traveling  crane. 

When  it  was  desired  to  transfer  UZ  and  Y from  one  hay  to  another, 
the  following  operations  were  necessary:  First,  a motion  at  right 
angles  to  the  axis  of  the  nave  for  a distance  of  17  meters,  so  as  to 
clear  Z and  V and  allow  them  to  pass  under  the  arched  girder;  sec- 
ond, a movement  of  21.50  meters  parallel  to  this  axis  to  the  following 
hay;  third,  a movement  at  right  angles  to  the  axis,  so  as  to  bring 
the  whole  back  into  line  with  its  primitive  position. 

These  travelers  were  carried  on  three  sets  of  rails,  two  across  and 
one  lengthwise,  by  means  of  fifty  wheels,  twenty-eight  for  the  first 
and  third  travelers,  and  twenty-two  for  the  second. 

The  height  of  the  axles  of  the  wheels  could  be  raised  enough  to 
enable  the  wheels  to  clear  the  rails,  by  removing  a set  of  cast-iron 
bearings  placed  above  the  axles  for  this  purpose. 

In  order  to  pass  from  one  line  of  rails  to  another,  the  travelers 
were  raised  by  a set  of  hydraulic  jacks,  the  upper  bearings  removed, 
the  wheels  pushed  up  and  wedged  into  their  frames,  and  the  set  of 
wheels  for  the  other  line  brought  down.  The  travelers  were  then 
moved  by  cables  attached  to  piles  driven  into  the  ground,  the  cables 
being  wound  up  on  the  winches  k and  7.  The  time  required  to  shift 

X,  Y,  and  Z,  was  a little  less  than  two  days. 

(379)  General  process  of  erection. — The  bed  plates,  cast-iron  pillow 
blocks,  were  fastened  by  the  anchorage  bolts  already  described.  The 
form  is  shown  in  Figs.  264  and  265. 

The  bed  plate  rests  on  a sheet  of  lead  5 millimeters  thick,  spread 
upon  a coating  of  Portland  cement  laid  upon  the  masonry. 

The  portions  of  one-half  of  the  girder,  consisting  of  the  foot,  the 
head  panel,  and  the  intermediate  sections  unriveted,  were  sent  from 
the  shop. 

The  traveling  crane  y,  10  meters  high,  was  used  to  handle  the  dif- 
ferent pieces,  which  were  put  together  in  two  separate  portions,  m 
and  n,  and  laid  parallel  to  each  other  (Fig.  263). 

Suppose  now  the  bay  H H'  I I'  to  be  finished ; we  pass  to  the  fol- 
lowing bay  thus  : X takes  the  position  X, ; Y,  the  successive  position 

Y,  and  Ya;  and  Z,  those  of  Z,  and  Z3.  Then  the  portion  of  the 
girder  n placed  upon  cars  running  on  a cross  track  is  brought  to  n', 
directly  under  the  pulleys  forming  the  hoisting  apparatus  on  X, 
while  the  foot  m is  dragged  to  the  position  m'  just  in  front  of  its 
bearings.  Ya  is  then  pushed  into  the  position  Y,  in  line  with  its 


CIVIL  ENGINEERING,  ETC. 


849 


first  position.  The  same  movements  are  made  with  Z.  The  two 
pieces  m'  and  n'  are  now  ready  to  he  raised. 

(380)  Erection  of  the  foot  of  the  girder.—  Fig.  204— The  first  opera- 
tion is  to  turn  P around  an  auxiliary  axle,  A,  until  the  rounded  edge, 
M,  of  O bears  upon  N.  S is  fixed  by  four  steel  wedges,  H,  to  the  bed 
plate  T.  which  is  made  fast  by  the  anchorage  bolts.  The  auxiliary 
axle  A is  a steel  cylinder  0. 12  meter  in  diameter  and  0.80  meter  long. 
It  rests  on  the  cast-iron  half  pillow  block  B bolted  to  the  oak  frame  E. 
The  half  pillow  block,  C,  of  the  axle  A is  fixed  upon  P by  bolts  and 


braced  by  two  iron  claws,  D,  riveted  to  the  girder  itself.  The  pieces 
C and  D are  subsequently  removed  and  the  holes  stopped  with  rivets. 

When  the  piece  P is  dragged  over  so  as  to  stand  exactly  in  front 
of  R,  it  is  lifted  by  hydraulic  jacks,  and  the  supports  are  gradually 
removed  until  C comes  in  contact  with  A.  The  hoisting  was  done 
H.  Ex.  410 — vol  hi 54 


850 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


by  means  of  a cable  and  two  pulleys — one  fixed  to  the  scaffolding  Z, 

and  the  other  united  by  an  oscillating  bar 
and  two  connecting  rods  to  a steel  axle 
fixed  to  the  lower  flange  of  the  fifth  panel 
(Fig.  2G(>),  so  that  the  different  pieces  could 
oscillate  at  right  angles  to  the  traction  in 
both  directions.  The  cable  was  0.075  meter 
in  diameter  and  had  been  tested  to  40  tons. 
The  foot  weighing  48  tons  and  bearing 
partly  upon  A.  its  axle  of  rotation,  with 
three  plies  of  the  cable  there  was  no  dan- 
ger of  rupture.  The  cable  passed  over  the 
winch  e and  was  worked  by  a gang  of 
twelve  men.  As  an  extra  precaution  the 
first  motion  of  the  girder  was  aided  by  the 
auxiliary  hoist  q.  Two  guys  steadied  p 
in  its  motion,  and  finally  the  traveler  Z 
was  guyed  by  a steel  cable  s.  It  took 
about  three  hours  to  raise  both  feet  to- 
gether. 

(381)  Erection  of  the  remainder  of  the 
girder. — When  each  foot  was  raised  and 
secured  to  its  traveler  the  joining  pieces  were  brought  into  place  by 
the  traveling  cranes,  h h,  and  were  riveted  on  the  scaffoldings. 


Fig.  26G.— Special  arrangement  of 
the  pulleys  for  lifting  the  foot  of  the 
girder  so  that  the  different  pieces 
may  oscillate  in  directions  at  right 
angles  to  each  other,  in  order  that 
the  traction  shall  always  be  normal 
to  the  axis  of  rotation. 


Fig.  267. — Scheme  adopted  by  Fives-Lille  Co.  for  erecting  the  rafters  and  purlins. 

The  other  portion  n'  of  the  girder  was  slung  at  its  extremities  to  the 
pulleys  d and  k by  three  cables  each,  so  that  the  section,  which  weighs 


CIVIL  ENGINEERING,  ETC. 


851 


about  38  tons,  Avas  borne  with  perfect  security.  The  inner  end  was 
first  raised  by  the  winch  d until  the  section  took  the  position  to',.  It 
was  then  raised  by  means  of  d and  k,  to  the  position  to',,  the  head 
being  about  2 meters  from  its  final  position  n\.  To  bring  it  to  the 
position  n\  the  winch  d was  stopped,  and  a second  pulley  ir  worked 
by  the  winch  / was  attached  to  the  end  of  girder. 


Fig.  263  shows  the  arrangement  of  these  two  pulleys.  By  hauling 
and  slacking  alternately  with  the  pulley  d,  the  bearing  of  the  head 
was  brought  to  the  trunnion  of  the  upper  joint.  The  raising  of  the 
other  section  was  carried  on  at  the  same  time  until  both  bearings 
closed  upon  the  trunnion.  When  this  was  done  the  collar  plates  were 
bolted  on,  uniting  the  two  bearings  together.  During  this  time  the 
two  sections  of  the  girder  were  being  riveted  together. 


852 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


The  operation  of  raising  the  whole  girder  took  five  hours  and  a 
gang  of  eighty  men  in  all. 

(382)  The  raising  of  the  purlins. — After  the  gutters  had  been 
raised  and  placed  by  the  cranes  h and  i,  purlins  Nos.  2,  3,  4 (Fig. 
2G7)  were  raised  and  placed  on  U'.  The  upper  extremities  were  fur- 
nished with  bushings  carrying  rollers  (Figs.  268  and  269). 

Then  the  three  purlins  with  their  six  rafters  were  riveted  together 
upon  the  floor  of  the  traveler.  The  whole  system  was  then  rolled 
by  two  winches  placed  on  the  central  traveler  and  hauled  to  its 
final  place;  the  rollers  were  taken  off,  the  cheeks  let  down  by  special 
jacks  arranged  on  wooden  frames;  the  purlins  came  into  their  proper 
places  and  were  bolted  to  gussets  riveted  to  the  girder  (Fig.  270). 

(383)  Weight. — 

Tons. 


Weight  of  each  gable-end  girder 240 

Weight  of  each  of  the  other  girders 196 

Weight  of  one-half  bay  including  the  purlins,  rafters,  and  sash  bars 62 

Weight  of  gutters,  arcade,  etc.,  for  one-half  bay 28 


Number  of  rivets  for  the  ordinary  girders,  about  32,000,  not  in- 
cluding those  for  the  purlins.  Of  these  19,600  were  driven  in  the 
shops,  10,300  on  the  ground,  and  2,100  on  the  scaffoldings. 

Number  of  workmen  employed  on  the  ground  daily,  250. 

The  first  girder  was  erected  April  20,  1888.  The  first  bay  was 
completed  in  23  days,  the  second  in  16  days,  the  third  in  12  days, 
and  each  of  the  following  bays  in  about  10  days. 

(384)  Method  of  erection  adopted  by  Gail  & Co. — The  system 
adopted  by  Cail  & Co.  was  devised  by  M.  Barbet,  chief  engineer 
of  the  company.  It  consisted  in  raising  the  girder  in  pieces  not 
exceeding  3 tons  and  riveting  them  directly  from  a single  scaffold- 
ing, the  top  of  which  conformed  as  nearly  as  possible  to  the  intrados 
of  the  arch. 

Fig.  27l  shows  the  elevation  of  this  great  scaffolding,  consisting 
of  five  stagings  16,  18,  and  20  meters  long,  by  8 wide,  connected  at 
a height  of  10  meters  by  a series  of  bridle  pieces;  the  stagings  are 
united  at  their  upper  parts  by  plank  floorings;  one  of  the  floorings, 
a flight  of  steps,  follows  the  outline  of  the  girder  which  it  is  intended 
to  support;  it  has  a width  of  5 meters;  the  other,  35  meters  high,  is 
horizontal. 

On  this  platform,  4 meters  wide,  two  rails,  2.50  meters  apart,  are 
laid,  which  carry  a traveling  crane,  shown  in  the  figure. 

The  five  stagings  are  mounted  on  twelve  wheels  0.60  meter  in 
diameter.  The  rails,  0.12  meter  high,  are  fixed  to  strong  cross-ties 
1.10  meters  by  0.25,  by  0.15,  0.70  apart  and  the  whole  carefully 
leveled. 

The  scaffolding  is  moved  by  five  winches  set  up  on  its  lower  fram- 
ing, and  the  ropes  pass  through  pulleys  made  fast  to  piles  driven 
into  the  ground.  Each  staging  was  provided  with  a plumb  line,  and. 


Fig.  271.  Erection  of  the  great  truss  girders.  Method  used  by  Cail  & Co.  View  of  the  girders  and  the  erecting  scaffolding. 


CIVIL  ENGINEERING,  ETC. 


853 


854 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS, 


Pio.  272.— Erection  of  the  great  truss  girders.  Method  used  by  Cail  & Co.  One  of  the  upper  platforms  of  the  rolling  scaffolding. 


855 


CIVIL  ENGINEERING,  ETC. 

as  all  the  rails  were  marked  in  divisions,  it  was  possible  to  correct, 
from  time  to  time,  irregularities  in  the  motions  of  the  different 
stagings.  The  shitting  of  the  scaffolding  for  one  hay  occupied  not 
more  than  1+  hours. 

In  addition  to  these  scaffoldings  there  were  two  large  traveling 
cranes,  8 meters  by  6,  and  28  high,  running  on  tracks  laid  outside  and 
parallel  to  the  axis  of  the  nave. 

(385)  Process  of  erection—  After  bolting  down  and  adjusting  the 
bed  plate,  the  bearings,  etc. , they  proceeded  to  erect  the  bases  of  the 


Fig.  273.— Method  of  erecting  the  purlins  adopted  by  Cail  & Co. 


girders  by  building  around  the  pier  a staging  which  was  capable  of 
holding  a flooring  at  any  height  below  the  gutters  ; pieces,  brought 
by  cars,  were  taken  by  the  cranes,  carried  up,  and  fitted ; a gang  of 
riveters  followed  the  fitters  as  the  work  went  on,  to  the  level  of  the 
gutters.  The  cranes  were  then  moved  on  to  the  next  pier  and  the 
operation  repeated. 

During  this  time  the  traveling  cranes  on  the  great  scaffolding 
(Fig.  272)  raised  and  placed  the  other  pieces  of  the  arch  which  were 
first  secured,  then  bolted  together.  The  two  half  arches  rose  pro- 
gressively together  to  the  upper  joint ; at  intervals  the  intrados  plate 
was  supported  on  pairs  of  jacks,  thirty-two  for  the  whole  girder, 
which  was  thus  held  a little  above  its  final  position  so  as  to  leave  a 
little  play  at  the  joint.  Whom  the  riveting  was  finished  the  half 


856 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


girders  were  dropped  into  their  proper  position  and  the  connecting 
collars  bolted  on. 

(38G)  Erection  of  the  purlins  and  rafters. — Figure  273  shows  the 
. method  by  which  the  purlins  and  rafters  were  placed.  One  end  of 
the  purlin  was  made  fast  to  the  chains  of  the  travelling  crane,  the 
other  end  to  a rope  from  sheers  erected  exactly  in  line  with  the  defi- 
nite position  of  the  purlin.  The  crane  was  moved  out  of  line  as  the 
hoisting  went  on,  until  the  purlin  had  cleared  the  flanges  of  the 
girders,  the  crane  was  then  brought  back  and  the  purlin  lowered 
into  its  place.  At  the  time  of  lowering  the  purlin,  an  aperture  was 
made  in  the  scaffold  flooring  by  taking  up  some  of  the  planks,  which 
were  replaced  when  the  operation  was  finished. 

The  rafters  were  raised  in  a similar  manner.  To  each  purlin 
were  fastened  six  outriggers,  coupled  at  the  right  of  the  angle  irons 
fastening  the  rafters;  these  outriggers  carried  pulleys  over  which 
ropes  passed  to  winches  on  the  ground.  The  rafters,  like  the  pur- 
lins, were  raised  by  these  winches. 

As  before  stated,  there  were  32,000  rivets ; of  these  4,000  were 
driven  in  the  workshop,  8,000  on  the  ground,  and  20,000  upon  the 
scaffoldings. 

The  average  number  of  workmen  was  215. 

The  first  girder  and  bay  were  completed  on  the  24th  of  May  ; the 
second  and  third  girders  and  bays  required  13  days  each  ; the  fourth 
and  fifth  12  days  each,  and  the  rest  10  days  each,  on  an  average. 

A view  of  the  gable  in  process  of  construction  is  given  in  Plate 
XIX,  and  a view  of  the  interior  of  one  end  of  the  hall  in  Plate  XX. 

(387)  The  great  vestibule. — The  central  30-meter  gallery  communi- 
cates with  the  Machinery  Hall  by  a vestibule  (Fig.  274),  which  unites 
it  with  the  lateral  galleries  of  the  great  nave.  This  vestibule  has 
two  wings  covered  by  hooded  arches  4.  GO  meters  wide,  each  contain- 
ing a monumental  staircase  leading  to  the  Machinery  Hall  gallery. 

The  iron  framework  consists  of  four  great  pillars  22  meters  high, 
which,  by  means  of  four  arches,  support  a belt  25.66  meters  in 
diameter,  resting  on  the  middle  of  each  arch.  A part  of  the  weight 
of  this  belt  is  borne  directly  by  the  pillars  by  means  of  struts  which 
form,  with  the  base  of  the  belt,  four  pendant  arches. 

The  roof  is  a cupola  formed  by  sixteen  curved  ribs  resting,  below, 
on  the  belt,  and  converging  to’ a second  belt  10  meters  in  diameter, 
which  supports  the  lantern.  The  latter  also  consists  of  sixteen  ribs 
0. 15  meter  wide,  springing  from  the  upper  belt  and  converging  to  a 
third  belt  1 meter  in  diameter.  The  ribs  are  braced  by  circular  pur- 
lins, which  support  the  sash  bars  and  that  part  near  the  gutters 
which  is  covered  with  zinc. 

The  roof  has  a double  glazed  ceiling.  A spherical  glazed  ceiling, 
hung  from  the  curved  ribs  by  iron  rods,  extends  upward  to  a perfor- 
ated circular  plate  suspended  from  the  lantern  ribs,  serving  as  a 


Paris  Exposition  of  1889 — Vol.  3. 


iims 


v 


VIEW  OF  MACHINERY  HALL,  SHOWINi 


Civil  Engineering,  etc  — rLATE  XIX. 


mm. 


WMMM, 


§jgjSl>3»T<i 


,g:he  end  truss  girder  and  the  gables. 


INTERIOR  VIEW  OF  MACHINERY  HALL. 


Fig.  274. — Cupola  of  the  vestibule  of  the  Machinery  Hall.  Transverse  section. 


857 


CIVIL  ENGINEERING,  ETC. 

means  of  ventilation.  This  double  ceiling  is  only  ornamental ; it  is 
entirely  glazed  except  at  its  lower  part,  and  is  divided  into  sixteen 
panels  made  up  of  a number  of  pieces  of  colored  glass  set  in  lead 

frames. 

The  portions  of  the  interior  of  the  dome  and  wing  not  glazed  are 
decorated  with  paintings  and  ornamented  plaster  and  ceramic  work. 


The  balustrade  of  wrought  iron  and  bronze  is  a work  of  great 
artistic  merit.  Two  bronze  figures  at  the  entrance,  by  MM.  Cor- 
donnier  and  Barthelemy,  carry  a group  of  twenty  incandescent  lamps. 

(388)  The  erecting  scaffolding  is  shown  in  Figs.  275  and  276;  it  is 
circular,  being  formed  of  two  framed  belts  of  the  same  size  as  those 
of  the  cupola.  The  exterior  belt  has  twelve  sides;  it  is  made  up 
of  sixteen  posts  united  by  four  courses  of  bridle  pieces  and  double 


858 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


diagonals.  Tlie  interior  belt  is  square,  formed  of  eight  posts  united 
like  the  preceding  ones. 

The  two  belts  are*  connected  with  each  other  by  sixteen  trestles, 
four  of  which  intersect  and  form  the  sides  of  the  interior  square. 


Figs.  275  and  276.— Transverse  section  and  plan  of  the  scaffolding  used  in  erecting  the  vestibule  of 

Machinery  Hall. 

The  dome  was  erected  by  means  of  wooden  shears  set  up  on  two 
wooden  platforms,  the  first  18.75  meters,  and  the  second  26.30  meters 
high. 


CIVIL  ENGINEERING,  ETC.  859 

The  constructors  of  the  iron  work  for  this  pavillion  were  MM. 
Monreau,  Fr&res. 

(389)  Decoration. — The  nave  is  covered  with'  ground  glass  fur- 


Machinery  Hai.l.  Side  Galleries. 


nished  by  the  Saint  Goban  Manufactory;  the  lower  parts  toward  the 
gutters  are  unglazed,  but  decorated  with  the  arms  of  the  principal 


860 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


cities  of  the  world  and  those  of  the  chief  towns  of  France  and  her 
colonies. 

(390)  Lateral  galleries  of  Mach  inery  Hall. — Figs.  277-279  show 
elevations  and  a section  of  the  lateral  galleries  annexed  to  the  great 
nave  of  Machinery  Hall.  The  galleries  are  on  the  two  long  sides 
of  the  great  nave  only  ; they  are  made  up  of  a series  of  arches. 

The  first  series  consists  of  the  arches  situated  between  the  great 
girders  and  united  with  the  vertical  part  of  the  spandrel,  in  which 
is  fixed  the  gutter  purlin  of  the  great  nave.  These  arches  brace  the 
great  girders  and  sustain  a flush  vertical  portion,  a sort  of  curtain 
which  closes  the  space  left  between  the  girders  above  the  arches. 


The  second  series  of  arches,  situated  15  meters  outside  the  first, 
is  identical  in  form  with  the  preceding,  but  of  a slightly  different 
construction.  The  two  series  are  united  by  a system  of  purlins  and 
rafters  supporting  a zinc  roofing. 

The  lateral  galleries  are  divded  into  two  stories  by  a flooring  8 
meters  above  the  ground;  on  this  flooring  the  grand  stands  are 
placed. 

The  facade  arches  are  formed  of  a girder  with  a full  web. 

This  girder  is  made  up  of  a plate  cut  according  to  the  profile  of 
the  arch,  having  its  upper  and  lower  members  formed  by  two  angle 

irons  by  90  an(j  a pja^e  300  by  g millimeters.  These  mem- 


Fio.  278. — Transverse  section  through  the  crown  of  the  arch. 


CIVIL  ENGINEERING,  ETC. 


861 


Machinery  hall.  Side  Galleries. 
n “ " " 


Fig.  279.— Side  galleries.  Lateral  view  from  the  principal  nave. 


862 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


bers  are  united  at  intervals  by  a certain  number  of  uprights  which 
stiffen,  and  serve  as  points  of  attachment  for  a series  of  brackets  and 
angle  irons  supporting  the  upper  crown  of  the  arch. 

For  all  the  portions  of  the  fagade  arches  and  also  for  the  interior 
part,  where  a purlin  is  fixed  to  an  upright,  the  uprights  are  formed 
by  four  angle  irons. 

At  the  interior  portion  of  the  arches  of  the  fagade  (Fig.  279),  and 
to  reproduce  the  lattice  of  the  arches,  plate-iron  bars  are  riveted  to 
the  girders.  This  lattice  only  serves  as  a decoration.  The  piers  of 
the  fagade  arches  are  the  same  as  those  of  the  interior.  These  piers 
support  a horizontal  girder  resting  on  two  intermediate  columns. 
The  floor  beams  are  joined  to  this  beam.  These  beams  are  attached 
on  the  interior  side  to  a girder  half  flush  and  half  lattice,  which 
spans,  without  support,  the  intermediate  space  of  21.50  meters  be- 
tween the  girders.  Above,  the  horizontal  fagade  girder  the  space 
is  filled  with  brick,  and  above  that,  with  glass  to  light  the  first  story 
of  the  galleries. 

The  ground  floor  is  lighted  by  a glazed  portion  situated  below  the 
horizontal  girder,  beginning  at  a distance  of  0.575  meter  above  the 
ground. 

The  decorations  of  the  annexed  galleries,  like  the  decorations  of 
the  great  nave,  are  very  simple,  and  indicate  clearly  the  utilitarian 
object  of  the  structure. 

(391)  The  construction  of  the  gable  ends  and  the  lateral  galleries 
(Plates  XIX  and  XX)  was  done  by  MM.  Baudet,  Donon  & Co.,  the 
gable  ends  and  galleries  attached  requiring  over  1,200,000  kilograms 
of  iron.  One  end  is  decorated  by  a great  glass  window,  consisting 
of  19  panels  9 meters  high,  representing  the  battle  of  Bouvines. 

The  opposite  end  is  flanked  by  two  towers,  and  bears  in  relief  the 
arms  and  attributes  of  the  city  of  Paris.  The  archivolt  is  decorated 
with  the  arms  of  the  principal  countries  taking  part  in  the  exhibi- 
tion. 

Plate  XXI  and  XXII  show  the  two  groups  of  figures,  10  meters 
high,  supporting  the  lintel  of  the  gable,  referred  to  elsewhere. 

(392)  Weight. 

The  total  weight  of  iron  used kilograms. . 12,761,063 

Total  surface  covered square  meters. . . 62,113 

Weight  per  square  meter  covered  . .kilograms. . 205.45 


Paris  Exposition  of  1889— Vol.  3. 


Civil  Engineering,  etc.-  PLATE  XXI 


A GROUP  OF  FIGURES  SUPPORTING  THE  LINTEL  OF  MACHINERY  HALL, 
AND  REPRESENTING  ELECTRICITY:  BY  M.  BARRIAS. 


Paris  Exposition  of  1889— Vol.  3. 


Civil  Engineering,  etc.  — PLATE  XXII 


A GROUP  OF  FIGURES  SUPPORTING  THE  LINTEL  OF  MACHINERY  HALL,  AND 
PERSONIFYING  STEAM  ; BY  M.  CHAPU. 


CIVIL  ENGINEERING,  ETC.  863 

Cost  of  Machinery  Hall. 

Francs. 

Earthwork  and  masonry 592,425. 54 

Ironwork  5,398,307.25 

Woodwork  ; 193,760.51 

Covering,  lead  and  zinc 236,682.74 

Floorings 78,591.04 

Joiner’s  work 34,345.86 

Glazing 182,242.67 

Decoration  256,141.50 

Painting 158,547.40 

Administrative  expenses,  etc 190,227.66 

Engineers,  etc 192,922.52 


Total 7,514,094. 69 


(393)  Acknowledgments. — In  terminating  this  extended  notice.  I 
wish  to  express  my  obligations  to  M.  Contamin,  chief  engineer  of 
the  building,  for  valuable  assistance  and  information. 

The  original  plans  and  descriptions  of  Machinery  Hall  were  pub- 
lished by  M.  Grosclaude,  M.  Contamin’s  assistant,  but  were  consid- 
erably modified  (iron  substituted  for  steel)  before  the  structure  was 
erected.  M.  Grosclaude  was  kind  enough  to  correct  his  plans  and 
descriptions  published  in  Le  Genie  Civil  and  also  furnish  me  with 
new  drawings  of  the  main  girder  and  its  details.  The  notice  of  the 
foundation  and  erection  are  from  the  description  of  M.  Henard, 
assistant  architect  of  the  building,  published  in  the  same  journal. 

To  Cail  & Co.,  and  especially  to  M.  Baudet,  contractor  for  the 
gables,  I am  indebted  for  photographs  and  for  much  valuable  in- 
formation. 


PART  V -LIGHT  HOUSES. 


Chapter  XLVII.— Planier  Light-house. 

(394)  At  a distance  of  8 miles  southeast  of  the  entrance  to  the 
port  of  Marseilles  is  a vast  mass  of  rocks  for  the  most  part  under 
water,  and  which  emerge  at  one  point  only,  where  they  form  the 
islet  of  Planier,  which  is  200  meters  in  length  from  east  to  west  and 
100  meters  in  breadth.  It  consists  only  of  rocks  and  has  a flat  sur- 
face, the  most  elevated  point  of  which  is  only  4.50  meters  above 
flood  tide ; in  the  heavy  swells  from  southeast  to  south  and  west,  the 
waves  cover  the  islet  to  the  approaches  of  the  light-house  tower. 

The  sides  of  the  islet  are  perpendicular,  but  several  little  creeks 
exist  where  it  is  possible  to  land  when  the  weather  is  favorable, 
care  being  taken  to  select  one  to  leeward.  They  are,  however,  very 
small,  and  have  not  more  than  1 or  2 meters  of  water,  owing  to  which 
circumstance  only  small  boats  can  enter  them. 

Being  situated  at  the  entrance  of  the  bay  of  Marseilles,  this  islet 
has,  from  time  immemorial,  been  pointed  out  to  navigators,  and  an 
old  tower  on  the  eastern  side  originally  served  as  a beacon.  In  1829 
it  was  considered  necessary  to  establish  at  Planier,  for  the  benefit  of 
vessels  making  the  land,  a light-house  which  would  be  visible  at  a 
great  distance,  and  a tower  was  constructed  on  the  west  side,  on 
which  was  placed  a light  of  the  first  order,  eclipsed  at  intervals  of 
30  seconds,  and  with  its  focus  3G  meters  above  the  ground  and  40  me- 
ters above  flood  tides. 

Owing,  however,  to  the  immense  development  of  the  maritime 
commerce  of  Marseilles,  and  because,  since  the  period  of  steam  navi- 
gation, the  speed  of  vessels  has  been  augmented  to  such  a degree,  it 
became  imperatively  necessary  to  render  the  approaches  of  the  port 
as  conspicuous  as  possible,  so  that  there  need  be  neither  error  nor 
hesitation  on  the  part  of  the  commanders  of  vessels  at  a long  dis- 
tance from  the  island.  It  was,  therefore,  decided  to  establish  here  a 
flashing  electric  light,  with  eclipses  at  an  interval  of  5 seconds,  a red 
flash  succeeding  three  white  flashes,  having  a range  of  about  23.04 
nautical  miles.  To  obtain  this  range,  so  superior  to  the  old  one, 
which  was  not  more  than  15.03  miles,  the  light  had  to  be  increased 
in  intensity,  the  oil  lighting  replaced  by  an  electric  light,  and  the 
tower  raised  40  meters,  that  is,  to  63,469  meters  above  low  tide.  As 
864 


865 


CIVIL  ENGINEERING,  ETC. 


the  existing  tower  was  not  high  enough  for  so  extensive  a range,  and 
the  nature  of  the  construction  did  not  admit  of  any  addition  to  its 
height,  the  erection  of  a new  tower  was  resolved  upon,  which  is 
shovvn  in  Figs.  280  and  281.  It  is  cylindrical  in  form,  built  of  rub- 
ble masonry  with  hydraulic  mortar.  Ashlar  is  used  only  for  the 


0 5 OOrniWb 

- ...  - - . i- 

Figs.  280  and  281.— Section  and  elevation  of  the  Planier  light  house. 

revetment  at  the  base,  and  for  the  cornice  and  parapet  at  the  crown. 
The  facing  of  the  shaft  consists  of  a layer  of  Portland  cement.  The 
staircase  is  of  ashlar.  The  base  rests  upon  a foundation  platform 
leveled  at  4.45  meters  above  low  water.  The  height  of  the  base 
H.  Ex.  410 — vol  hi 55 


866 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


above  tliis  platform  is  8.  GO  meters,  that  of  the  shaft  42.44  meters,  and 
that  of  the  crown  5.45  meters.  The  focus  is  59.019  meters  above  the 
platform  foundation.  The  radii  of  the  horizontal  sections  of  the 
tower  are  as  follows  : 3.35  meters  for  the  top  of  the  shaft,  4.40  meters 
at  its  base,  and  G.90  meters  at  the  bottom  of  the  basement.  The  in- 
terior space  forming  the  staircase  is  a cylinder  4 meters  in  diameter. 
It  is  lighted  by  twenty-five  windows.  The  stone  stairway,  0. 80  meter 
wide,  stops  on  the  two  hundred  and  fifty-fourth  step.  It  is  prolonged 
by  an  iron  staircase  of  sixteen  steps  reduced  to  0.60  meter.  This 
last  goes  through  the  arch  upon  which  the  flooring  of  the  service 
chamber  rests,  at  a height  of  49.08  meters  above  the  sill  of  the  en- 
trance. This  chamber  is  lighted  by  four  windows  pierced  between 
the  brackets  of  the  coping  and  facing  in  the  direction  of  the  four 
cardinal  points.  A second  iron  staircase  of  twenty-one  steps  leads 
through  another  arch  to  the  lantern,  which  is  contained  in  a little 
stone  tower  2 meters  high,  which  forms  the  base  of  the  lantern  and 
surmounts  the  coping  of  the  light-house.  The  iron  lantern  is  4 me- 
ters diameter  inside.  The  light-house  is  protected  by  a lightning 
rod. 

(395)  Lighting  apparatus. — In  order  to  avoid  confusing  the  Plan- 
ier  light-house  with  those  in  the  vicinity,  and  as  the  electric  light  is 
very  appropriate  for  producing  flashes,  it  was  decided  to  give  the 
new  apparatus  the  character  of  a flashing  light  with  three  white 
flashes  and  one  red  one. 

The  optical  system  which  has  been  adopted  consists  of  a dioptric 
apparatus  with  a fixed  light,  0.60  meter  in  interior  diameter,  sur- 
rounded with  a movable  drum  of  vertical  lenses  consisting  of  six 
groups  of  four  lenses,  one  red  and  three  white,  making  a revolution 
in  90  seconds.  The  lenses  intended  to  produce  the  red  flashes  include 
a space  of  30  degrees;  those  which  give  the  white  flashes  extend  only 
over  10  degrees;  hence  there  is  an  interval  of  2^  seconds  between  the 
white  flashes,  and  5 seconds  between  each  red  flash  and  the  succeed- 
ing white  flash.  The  machine  which  produces  the  regular  rotation 
of  the  drum  is  lodged  in  the  base  of  the  apparatus. 

The  driving  weight  is  about  150  kilograms;  it  descends  in  a pit 
arranged  in  the  masonry  wall  of  the  tower  and  its  fall  is  about  0.90 
meter  per  hour. 

(39G)  Machinery. — The  apparatus  for  producing  the  electricity  is 
double.  It  is  formed  of  two  distinct  groups  set  up  in  a separate 
house  and  arranged  so  that  either  steam  engine  can  drive  either 
magneto-electric  machine.  The  steam  engines  are  horizontal,  with 
surface  condensation  ; having  separate  boilers  and  forming  two  in- 
dependent systems.  Each  boiler  is  furnished  with  two  steam  pipes 
so  that  it  can  feed  either  engine.  The  boilers  are  rated  at  5 kilo- 
grams per  square  centimeter;  the  power  of  each  is  5 horse  power, 
which  can  be  raised  to  10. 


CIVIL  engineering,  etc. 


867 


on^h  w if- Pr0d“Cevd  at  Planier  ^ magneto-eleotric  machines 

capable  of  furnishing  a light  of  85  Carcel  lamp.,  per  horse  power. 

e current  is  transmitted  to  an  electric  regulator  by  a commu- 

tator,  which  allows  the  machines  to  be  coupled  either  for  intensity 

or  quantity,  and  for  using  them  successively  or  separately 

The  ordinary  light  is  400  Carcel  burners  and  can  be  carried  to  800 

The  luminous  range  of  the  flashes  is  48.02  nautical  miles  for  the 

22  n"?,ru  at™0sl>hel;lc  conditions.  The  actual  geographical  range  is 

mi"  ? fOT  al'  oWver  at  4 50  m«ters  above  the  level  of  the  sea 
The  cost  was  474,776  francs. 

The  plans  were  prepared  by  MM.  Bernard,  Chief  Engineer,  and 
Andre  iinder  the  threchon  of  M.  Leonce  Raynaud,  Director  of  the 
Eight-House  Service. 


Chapter  XL\  III.— Iron  light-house  at  Port  Vendres. 

(307)  To  facilitate  the  entrance  and  exit  of  steamers  plying  regu- 
larly between  Port  Vendres  and  Algeria  a light-house  has  been  con- 
structed upon  the  pier  head  erected  for  the  protection  of  this  port 
against  heavy  seas.  1 

On  account  of  local  circumstances  exceptional  difficulties  were  met 
with  m this  construction. 

On  one  hand,  they  were  obliged  to  guard  against  the  consequences 
of  the  settling  of  the  foundations  of  the  pier  head,  which  was  built 
on  artificial  blocks  according  to  the  usual  process  adopted  in  the  Medi- 
terranean. Again,  it  was  necessary  to  arrange  the  edifice  so  as  to 
lodge  the  keeper,  and  to  resist  the  great  violence  of  the  waves,  for 
the  parapet  of  the  pier  head  was  only  4 meters  above  the  level  of  low 
tide,  entirely  insufficient  in  great  tempests  to  prevent  the  waves  from 
breaking  over  it  and  striking  the  light-liouse. 

Under  these  circumstances  the  idea  of  constructing  a masonry 
light-house  was  abandoned,  as  well  as  one  with  an  iron  frame  work, 
on  account  of  the  influence  of  the  waves  in  causing  vibrations,  and 
loosening  the  screws  of  the  tie  rods. 

It  was  finally  decided  to  build  this  edifice  (Figs.  282  and  283)  upon 
six  upright  hollow  iron  pillars  14.50  meters  long  arranged  in  the 
form  of  a regular  hexagon  2.20  meters  on  each  side.  Each  of  these 
uprights  is  formed  of  three  parts.  The  lower  part,  which  has  an 
exterior  diameter  of  0.30  meter,  0.03  meter  thick,  is  built,  for  a 
length  of  2 meters,  into  the  mass  of  the  masonry  and  united  by  a 
coupling  collar  to  the  middle  portion,  which  has  the  same  diameter 
and  a thickness  calculated  according  to  the  stress.  The  upper  part 
is  screwed  to  the  middle  part,  and  fastened  at  its  upper  extremity  to 
the  iron  floorings  of  the  platform  and  the  service  room. 

The  walls  of  the  latter  are  formed  of  plate  iron,  which  completes 
the  bracing.  It  is  cased  on  the  inside  with  woodwork.  The  floor 
and  the  ceiling  are  equally  of  wood.  Access  to  the  lantern  is  ob- 


868 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


tained  by  a spiral  staircase.  The  risers  are  of  cast  iron,  curved, 
movable  around  the  newel  post,  and  resting  on  four  pieces  which 
allow  them  to  turn  easily  without  the  upper  risers  obstructing  the 
motion.  The  steps  and  hand  rail  are  removable  ; hence  in  a threat- 
ening time  they  are  rapidly  taken  away,  and  all  the  risers  are  placed 
according  to  the  direction  of  the  waves  so  as  to  avoid  almost  com- 


o ' ' 5 ' ' ' io  is  Metres' 

Fig.  282.— Iron  light-house  at  Port  Vendres. 

i 

pletely  being  struck  by  the  waves.  Under  these  circumstances  the 
risers  form  a vertical  ladder,  which  also  gives  access  to  the  chamber 
and  the  lantern. 

Arrangements  are  made  so  that  the  keeper  may  remain  without 
communication  with  land  during  heavy  weather. 


mm. 


CIVIL  ENGINEERING,  ETC. 


809 


For  about  four  years  the  light-house  lias  been  in  regular  operation 
without  accident,  notwithstanding  tempests  of  exceptional  violence 
during  the  winter  1887-88,  which  destroyed  a portion  of  the  jetty 


t — n t T U 

Fio.  283. — Section  and  plan  of  the  lodging  room  of  Port  Vendres  Light -house. 

and  carried  away  the  parapet.  Great  dashes  of  spray  frequently 
covered  the  lantern,  put  out  the  fire,  and  broke  the  glass  in  the 


870 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


keeper’s  room.  Nevertheless  neither  the  security  of  the  service  nor 
the  stability  of  the  construction  has  been  endangered.  The  results, 
therefore,  may  be  considered  satisfactory  in  every  respect. 

Cost. — The  cost  was  59,489  francs. 

The  light-house  was  planned  and  erected  under  the  direction  of  M. 
Leferme,  general  inspector,  by  M.  Bourdelles,  chief  engineer ; M. 
Barbier  & Co.  built  the  iron  superstructure. 

Chapter  XLIX — Apparatus,  2.66  meters  in  interior  diameter, 

CALLED  HYPER-RADIANT,  FOR  LIGHTING  CAPE  ANTIFER. 

(398)  The  apparatus  for  a light-house,  called  hyper-radiant,  ap- 
pears in  a universal  exhibition  for  the  first  time. 

It  may  not  be  out  of  place  to  call  to  mind  that  the  first  lenticular 
apparatus  which  Fresnel  made  for  the  light-house  at  Corduan,  in 
1822,  was  a first-class  light,  having  a diameter  of  1.84  meters,  the 
same  as  all  those  hitherto  constructed.  And  although  important 
improvements  have  been  made  in  the  lenses,  yet  there  has  never 
been  hitherto  an  apparatus  constructed  of  greater  diameter. 

M.  Barbier,  toward  the  end  of  1885,  succeeded  in  constructing  a 
great  annular  lens  of  one-sixth,  having  a focal  length  of  1.33  meters 
and  an  angular  aperture  of  G5  degrees  in  the  vertical  plane.  This 
lens  was  tried  at  South  Foreland  in  1885,  and  compared  with  the 
greatest  of  the  lenses  of  the  first  order,  and  especially  with  a lens 
of  English  construction  similar  to  that  of  the  new  Eddystone  Light- 
house, a lens  of  0.92  meter  focal  distance,  which  occupies  equally  60 
degrees  in  the  horizontal  plane,  and  subtends  an  angle  of  92  degrees 
in  the  vertical  plane. 

Photometric  measurements  made  by  Prof.  Harold  Dixon,  of  Bal- 
liol  College,  Oxford,  on  the  13th  of  October,  1885,  showed  that  the 
illuminating  power  of  the  lens  of  1.33  meters  focal  length  compared 
to  the  Eddystone  lens  (the  two  lenses  illuminated  by  the  same  lamp) 
was,  for  the  first  series  of  experiments,  as  62.2  to  31.8,  and  for  the 
second  series,  in  the  ratio  of  28.9  to  13.7. 

If  we  consider  that  the  lens  of  the  Eddystone  type  has  an  angle  of 
92  degrees  in  the  vertical  plane,  while  the  latter,  corresponding  to 
the  lens  of  1.33  meters,  has  only  65  degrees,  we  see  that  the  illuminat- 
ing power  of  this  last  is  not  simply  twice  but  nearly  three  times  as 
great. 

This  apparatus  was  shown  in  the  pavilion  of  the  minister  of  pub- 
lic works. 

(399)  Apparatus  for  Cape  Antifer. — The  first  liyper-radiant  appa- 
ratus to  be  placed  on  the  French  coast  will  be  for  the  new  light-house 
on  Cape  Antifer,  near  Havre  (Fig.  284).  The  optical  apparatus 
which  is  2.66  meters  in  interior  diameter,  consists  of  six  annular 
panels  each  one  occupying  a sixth  of  a circumference  and  including 


CIVIL  ENGINEERING,  ETC.  871 

twelve  lower  catadioptric  elements,  ten  upper  dioptric  intermediate 
elements,  and  twenty-six  upper  catadioptric  elements. 

The  optical  apparatus  is  placed  on  a cast-iron  frame  formed  of  six 


FlQ.  284.— Half  elevation,  half  section,  and  plan  of  the  hyper  radiant  apparatus  for  the  new  light- 
house at  Cape  Antifer,  near  Havre. 

columns  supporting  a circular  entablature  and  a central  table  which 
is  accessible  by  a liight  of  steps.  Upon  this  base  a car  with  conical 


872 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


steel  wheels  carries  the  frame  of  the  apparatus,  of  which  the  base  is 
formed  by  a movable  plate  with  its  toothed  circumference  gearing 
with  the  pinion  of  the  driving  machine.  The  clockwork  of  this 
machine  turns  the  apparatus  completely  in  120  seconds,  so  as  to  pro- 
duce flashes  every  20  seconds,  followed  by  total  eclipses  of  the  light. 

The  machine  has  an  automatic  break  and  an  electric  .alarm  for  the 
slowing  and  stopping,  as  well  as  an  arrangement  for  winding  up  the 
weight  without  interrupting  the  rotation.  This  apparatus  will 
presently  be  described. 

The  cost  of  the  apparatus  was  94,000  francs. 

Chapter  L. — Improvements  in  the  apparatus  for  light-houses 

USING  MINERAL  OIL. 

(400)  The  reconstruction  of  the  Faraman  light-house  and  the  intro- 
duction into  the  new  edifice  of  a flashing  light  of  the  third  class, 
afforded  an  opportunity  for  bringing  together  the  different  improve- 
ments which  have  recently  been  introduced  into  several  French  light- 
houses burning  mineral  oil.  These  were  shown  at  the  exhibition. 

Multifocal  optical  apparatus. — It  is  the  general  custom  to  con- 
struct the  dioptric  elements  of  the  annular  lenses  and  the  cylindrical 
and  vertical  elements,  employed  in  the  optical  apparatus  of  light- 
houses, with  a common  focus.  The  same  rule  is  applied  to  the  cata- 
dioptric  rings,  and  there  has  been  hitherto  only  one  exception. 

This  manner  of  proceeding  would  be  required  if  the  lenses  were 
formed  of  a single  piece,  but  it  can  not  be  justified  for  those  in 
echelons  or  steps  in  use  in  light-houses,  and  still  less  for  the  catadi- 
optric  rings;  for  the  elements  which  compose  them  must  be  calcu- 
lated and  constructed  separately.  It  is  easy  to  perceive  that  it  does 
not  realize  either  the  maximum  useful  effect  of  the  light,  nor  the 
best  distribution  of  the  light  upon  the  surface  of  the  ocean,  and 
that  these  results  can  not  be  obtained  except  under  the  condition  of 
assigning  to  each  element  a special  focus  placed  in  the  most  favor- 
able position. 

By  determining  thus  the  different  foci  of  the  elements  of  a cylin- 
drical lens  we  find  that  they  should  be  taken  upon  the  axis  of  revo- 
lution above  the  focus  of  the  central  lens  and  at  a height  increasing 
with  the  distance  of  the  elements  from  the  focal  plane  of  this  lens. 

This  method  of  distributing  the  foci  is  not  adapted  to  the  annular 
apparatus  the  elements  of  which  are  obtained  by  revolution  around 
a horizontal  axis;  but  it  is  easy  to  recognize  that  one  may  realize 
the  desired  effects  by  taking  the  foci  on  this  axis,  as  in  the  preced- 
ing case,  with  this  difference:  that  the  elements  situated  above  the 
central  lens  have  their  foci  to  the  left  of  that  of  the  lens,  and  the 
lower  elements  to  the  right.  In  virtue  of  these  arrangements  the 
contiguous  edges  of  two  successive  rings  are  formed  of  two  concen- 
tric circles  of  the  same  radius,  which  come  together  and  unite  per- 


CIVIL  ENGINEERING,  ETC. 


873 


fectly  witliout  either  space  between  or  superposition.  We  thus 
avoid  the  defects  of  the  ancient  annular  pieces  of  apparatus,  at  the 

place  of  contact  of  the  dioptric  elements 
with  the  catadioptric  rings,  which  have 
a distinct  focus  placed  outside  of  the 
axis  of  revolution. 

Thus  multiplicity  of  foci  does  not 
complicate  either  the  calculation  or  the 
optical  construction,  and  presents,  con- 
sequently, advantages  without  any  in- 
convenience. 

The  new  apparatus  of  the  Faraman 
light-house  is  multifocal.  It  consists 
of  five  panels,  each  formed  of  twoun- 
symmetric  lenses,  having  their  princi- 
pal axes  at  an  angle  of  2.‘3  degrees.  Its 
flashes  are  thus  emitted  in  groups  of 
two.  In  each  group  they  last  a second, 
and  are  separated  by  a little  eclipse  of 
two  seconds.  A great  eclipse  of  six 
seconds  separates  each  group  from  that 
which  precedes  and  follows  it.  The 
apparatus  revolves  once  in  fifty  sec- 
onds. 

(401 ) Spherical  reflector. — As  the  Far- 
aman light  illuminates  only  half  of 
the  horizon,  it  becomes  convenient  to 
utilize  the  light  lost  on  the  land  side 
and  to  send  it  toward  the  sea  by  means 
of  a spherical  reflector.  But  it  has  not 
been  judged  necessary  to  give  to  this 
reflector  a radius  sensibly  equal  to  that 
of  the  lenses  as  has  been  hitherto  done. 
It  is  easy  to  see  that  the  result  to  be 
obtained  is  independent  of  this  radius, 
and  that  one  can  reduce  without  incon- 
venience its  length  according  to  the 
convenience  of  the  service  or  of  the 
construction. 

Under  these  conditions  it  is  easy  to 
make  the  reflectors  of  molded,  or  even 
of  blown,  glass  with  great  economy;  a 
slight  retouch  by  grinding,  suffices  to 
assure  the  proper  regularity  of  the  in- 
terior and  exterior  surface;  the  latter 
is  then  silvered  and  covered  with  a protecting  varnish.  Reflectors 


Figs.  285  and  286. — Vertical  and  hori. 
zontal  sections  of  an  apparatus  lighted 
with  petroleum  oil. 


874  UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 

are  thus  made,  at  little  expense,  which  utilize  about  a third  of  the 
incident  light,  and  are  easily  placed  in  all  optical  apparatus. 

(402)  Clockwork. — The  clockwork  and  the  frame  have  been  the 
object  of  various  improvements,  many  of  which  have  been  intro- 
duced in  France.  Among  these  we  may  mention: 

First.  The  substitution  of  conical  wheels  for  spheres,  previously 
used,  for  the  rolling  chariot. 

Second.  The  winding  apparatus  for  the  weight,  permitting  this 
weight  to  be  raised  without  stopping  the  machine. 

(403)  Automatic  brake  and  regulator. — That  the  rotation  shall  be 
uniform,  requires  the  action  of  the  weight  to  be  always  equal  to  the 
passive  resistances  which  it  has  to  overcome.  When  these  increase 


Fig.  287.— Regulating  brake  and  indicator  of  stoppage. 


from  any  cause  the  apparatus  is  liable  to  frequent  stoppages.  To 
obviate  these  we  must: 

First.  Give  the  moving  weight  an  extra  load  which  shall  render 
it  capable  of  putting  the  machine  in  motion  and  overcoming  the 
friction  of  its  parts  at  the  beginning. 

Second.  Counteract,  during  the  motion,  the  effect  of  this  extra 
load,  which  tends  to  accelerate  the  velocity. 


875 


CIVIL  ENGINEERING,  ETC. 

The  combination  lias  been  realized  by  means  of  a conical  pendu- 
lum (Fig.  28 1 ),  each  arm  of  which  is  furnished  with  a stirrup  pierced 
with  a hole,  in  which  a properly  balanced  rod  can  slide.  This  rod 
carries  at  its  lower  part  a wooden  or  a cork  button,  which  rubs  upon 
the  interior  surface  of  a spherical  segment  when  the  speed  of  rota- 
tion brings  the  arms  of  the  pendulum  to  their  normal  distance  apart. 
The  friction  ceases  automatically  when  the  arms  approach  each 
other  in  consequence  of  the  rotation  becoming  slower  or  stopping. 
In  the  latter  case  a stop  prevents  the  rod  from  descending  and  the 
center  of  the  segment  is  situated  a little  above  that  of  the  circum- 
ference described  by  the  button  when  the  rod  rests  upon  its  stop. 

With  this  arrangement  the  surcharge  is  free  if  the  machine  is  at 
rest,  and  its  action  determines  the  motion,  which  accelerates  until  the 
branches  of  the  pendulum  have  taken  their  normal  distance  apart. 
At  this  moment  the  work  of  the  load  is  equalized  by  that  of  the  fric- 
tion, on  account  of  the  path  which  the  button  describes  upon  the 
segment  and  the  pressure  exerted  by  the  loaded  rod  on  account  of 
the  centrifugal  force.  The  movement  then  becomes  uniform,  and 
the  rotation  is  maintained  in  the  required  conditions  as  long  as  the 
passive  resistances  remain  constant.  If  they  diminish  slightly  the 
rotation  is  accelerated,  the  distance  apart  of  the  pendulum  balls,  as 
well  as  the  work  of  the  friction  increases,  and  the  uniform  motion 
is  reestablished.  It  is  the  reverse  in  the  case  where  the  resistances 
increase.  The  brake  works  thus  as  a regulator  and  has  great  sensi- 
bility. 

It  is  evident  that  in  varying  the  load  and  the  path  of  the  rods  this 
arrangement  will  accommodate  itself  to  all  the  motions  of  the  clock- 
work. 

(404)  Electric  indicator  of  the  stoppage  of  the  apparatus. — These 
machines,  notwithstanding  the  intervention  of  the  brake,  may.  not- 
withstanding, stop,  if  the  keeper  is  negligent,  and  especially  if  he 
forgets  to  wind  up  the  weight  at  the  proper  time.  It  has  therefore 
been  considered  prudent  to  signalize  such  an  accident  by  an  electric 
bell.  It  is  put  in  motion  by  the  arms  of  the  pendulum  when  they 
fall  on  account  of  the  slowing  or  stopping  of  the  machine.  Their 
weight  then  overturns  an  ebonite  box  containing  mercury.  This 
liquid  closes  the  electric  circuit  having  its  two  poles  in  the  box. 

(405)  Constant  level  lamp. — The  old  lamps  have  been  replaced  by 
lamps  on  a new  model  wit li  a constant  level.  They  consist  of  a cyl- 
indrical copper  reservoir  furnished  at  its  lower  part  with  a neck 
which  can  be  opened  or  shut  at  will  with  a cock.  A central  tube, 
open  at  its  extremities,  passes  through  the  bottom  of  an  upper  com- 
partment of  the  reservoir,  arranged  like  a tunnel,  and  descends  to 
the  lower  part  of  the  neck.  Another  vertical  tube  emptying  on  the 
exterior  of  the  neck  rises  to  the  upper  part  of  the  reservoir,  with 
which  it  communicates.  The  neck  dips  into  a little  tank,  from 
whence  starts  the  feeding  tube  for  the  wick  and  that  of  the  overflow. 


876 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


To  fill  the  lamp,  the  cock  in  the  neck  is  closed  and  the  oil  is  poured 
upon  the  tunnel,  and  runs  into  the  reservoir  hy  means  of  the  central 

tube,  driving  the  air  into  the  lateral 
tube,  whence  it  escapes  into  the  at- 
mosphere. When  the  reservoir  is 
filled  the  cock  is  opened,  the  oil  flows 
into  the  tank  until  its  level  has  at- 
tained the  lower  orifice  of  the  central 
tube,  that  is  to  say,  a constant  level.  * 
From  this  moment  the  central  tube  is 
empty,  the  lateral  tube  is  full  up  to 
the  level  of  the  oil  in  the  reservoir, 
and  the  lam})  is  ready  to  work.  If 
we  open  the  wick  cock  it  may  be 
lighted.  As  the  oil  is  consumed  its 
level  lowers  in  the  tank  and  opens  the 
orifice  in  the  central  tube  by  which  air 
escapes,  making  the  requisite  quan- 
tity of  oil  flow  into  the  tank  so  as  to 
reestablish  the  constant  level. 

The  lamp  is  fixed  upon  one  of  the 
uprights  of  the  lantern. 

It  communicates  with  the  wick  by 
means  of  tubes  which  pass  under  the 
frame  and  rise  in  a central  column 
which  supports  the  burner.  This  ar- 
rangement makes  the  service  easier, 
especially  for  apparatus  of  small  di- 
mensions, like  those  of  the  third  class. 
It  avoids  all  the  inconveniences  of 
moderator  lamps  and  properly  feeds 
the  wick. 

Cost. — The  expense  of  the  apparatus 
for  the  Faraman  light-house  amounts 
to  23,300  francs. 

M.  Bourdelles,  engineer  in  chief  of 
the  service,  made  the  plan  under  the  direction  of  M.  Emile  Bernard, 
general  inspector  and  director  of  the  liglit-house  service. 

Chapter  LI. — Improvements  recently  made  in  electric  light- 
houses. 

(406)  Important  improvements  have  been  recently  made  in  the 
electric  illumination  of  the  French  coast.  This  illumination  is  con- 
fined at  present  to  eight  important  points,  viz,  Dunkirk,  Calais, 

*When  the  lower  cock  is  opened  the  air  in  the  reservoir  is  slightly  rarified.  by 
the  oil  passing  into  the  tank.  The  outer  air  enters  the  central  tube  and  clears  it, 
and  as  the  oil  rises  it  is  forced  up  the  lateral  tube  as  high  as  the  level  of  the  oil  in 
the  reservoir. 


^ : 

Ly  ^ 

O 

i 

w 

Flos.  288  and  289.— Elevation  and  plan  Of 
a constant  level  lamp. 


CIVIL  ENGINEERING,  ETC.  877 

Gris-Nez,  La  Canche,  La  Hbve,  Crdach,  Les  Baleines,  and  Planier. 
Five  others  are  in  process  of  erection. 

Bifocal  apparatus. — The  small  dimensions  of  the  optical  apparatus 

Recent  improvements  in  electric  lioht-houses. 


(0.60  meter  in  diameter)  have  been  preserved.  The  apparatus  itself 
consists  of  annular  unsymmetric  lenses,  preserving  the  character  of 


878 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


the  electric  light  (flashing  with  groups  of  two,  three,  or  four  flashes), 
which  is  thoroughly  appreciated  by  seamen.  This  arrangement  of 
the  optical  apparatus  enables  the  horizontal  angle  subtended  by  the 
lenses  to  be  augmented,  consequently  the  intensity  of  the  light  in- 
creased. (Figs.  290  and  291). 

The  latter  is  still  further  increased  by  the  suppression  of  the 
horizontal  divergence  artificially  given  to  the  lenses  in  the  vertical 
elements  of  the  old  apparatus. 

As  to  the  vertical  divergence,  it  has  not  been  thought  best  to 
increase  it  artificially. 

This  bifocal  arrangement  is  the  most  advantageous  and  the  most 
appropriate  for  electric  lighting,  and  it  has  accordingly  been  intro- 
duced into  the  new  apparatus. 

Caloric  engines  as  motors  have  been  substituted  for  portable  en- 
gines, three,  of  9-horse  power,  being  placed  in  each  light-house.  A 
single  one  is  sufficient  in  ordinary  times,  but  two  are  used  in  case  of 
fog,  or  to  work  the  fog  horns.  The  third  is  used  as  a reserve. 

The  magneto  electric  machines  used  are  those  of  M.  (le  M tritons, 
which  have  been  entirely  satisfactory  in  all  respects.  A number  of 
modifications  have  been  introduced,  viz  : 

The  arrangement  of  the  bobbins. — Eight  have  been  coupled  for  ten- 
sion, i.  e.,  one-half  in  each  of  the  five  disks  making  up  a magneto- 
electric machine.  The  five  half  disks  are  coupled  quantitively,  so  as 
to  divide  each  machine  into  two  half  machines  having  separately 
five  groups  of  eight  bobbins  in  tension.  Finally,  by  a commutator 
arranged  for  the  purpose,  two,  three,  or  four  half  machines  may  be 
quantitively  combined. 

On  the  other  hand,  it  is  not  necessary  to  couple  two  machines  when 
they  are  in  use  so  as  form  a single  machine.  The  same  result  is 
obtained  by  leaving  them  separate  and  driving  them  by  a single 
belt.  This  is  accomidished  by  interposing  between  the  machines  a 
short  shaft,  the  prolongation  of  those  of  the  machines,  carrying  two 
loose  pulleys,  so  that  the  drivingbelt  can  be  thrown  on  or  off  of  either. 

(407)  Working  of  the  system. — The  system  of  magneto-electric 
machines  and  their  accessories  allows  the  variation  of  the  intensity 
of  light  according  to  the  condition  of  the  atmosphere. 

The  following  table  shows  the  different  intensities  admitted  in  the 
service  and  the  means  of  obtaining  them  : 


Weather 

Clear. 

Ordinary. 

Mist. 

Fog. 

Diameter  of  the  carbon  points,  in  millimeters 

10 

10 

20 

23 

Number  of  magneto-electro  machines  in  use 

Mechanical  measures: 

I 

1 

U 

2 

Number  of  revolutions  per  minute  

430 

430 

430 

430 

Horse  power  on  shaft  (f),  circuit  closed  with  the  lamp. 

2.34 

3.80 

5.80 

7.50 

CIVIL  ENGINEERING,  ETC. 


879 


Weather 

Fog. 

Mist. 

Electrical  measurements: 

Intensity  (I)  in  ampOres: 

Circuit  closed  without  the  lamp 

33 

82 

150 

98 

Circuit  closed  with  lamp 

Electro-motive  force  (E)  in  volts: 
Open  circuit 

Closed  with  lamp 

Energy  in  watts  (E  I).- 

Circuit  closed  with  lamp 

902 

160 
350,000 
64  3 

44 

4,312 

738 

600,000 

Photometric  measurements: 

Horizontal  intensity  (L)  of  the  electric  lamp  in  Carcel 

burners 

Intensity  of  the  beam  of  light  emitted  measured  at  a 
distance  of  400  meters 

360 

500 

Efficiency: 

Carcel  burner  power  per  horse  power 

85.3 

6.4 

0.77 

77.6 

Number  of  burners  per  ampere 

6.5 

.54 

Ou.  O 

Efficiency  / E I \ 

0.71 

0.78 

V 75  g t ) 

In  clear  weather,  i.  e.,  ten-twelfths  of  the  year,  the  luminous  range 
of  the  new  electric  light  exceeds  27  miles,  which  is  amply  sufficient. 
For  the  other  two-twelfths  the  luminous  range  is  insufficient  on  ac- 
count of  the  fogs,  hut  it  is  impossible  to  remedy  this  defect  without 
an  outlay  entirely  out  of  proportion  to  the  results  to  be  attained. 

(408)  Electric  regulator.— The  electric  service  as  previeusly  de- 
scribed could  not  employ  M.  Serrin’s  regulators  except  by  modify- 
ing them  and  adapting  them  to  the  new  conditions  of  electric  light- 
ing. This  has  been  accomplished  as  follows: 

The  current  of  a demi-magneto  before  passing  to  the  lower  car- 
bon point  passes  through  an  electro-magnet  acting  on  a rod  of  soft 
iron  carrying  the  detent  which  serves  to  separate  the  star  wheel 
from  the  regulator.  This  rod  is  suspended  from  a horizontal  axle 
around  which  it  can  oscillate.  It  is  placed  at  the  proper  distance 
from  the  poles  of  an  electro-magnet  by  means  of  a bent  lever  driven 
by  a screw  and  furnished  with  two  spiral  springs  acting  in  oppo- 
site directions.  (Fig.  292). 

With  this  simple  arrangement  the  variations  in  the  resistance  of 
the  voltaic  arc  and  those  of  the  current  resulting  therefrom  deter- 
mine the  oscillation  of  the  soft  iron,  the  escape  of  the  detent,  and 
the  proper  distance  between  the  two  carbon  points. 

It  may  be  noticed  also  that  the  new  arrangement  of  escapement  is 
independent  of  the  lower  carbon  point.  When  the  electric  lighting 
requires  more  than  one  demi-magneto,  the  circuit  of  the  supple- 
mentary machines  is  connected  directly  with  the  carbon  points 
by  means  of  brushes  which  allow  the  motion  of  the  carbon-point 
holders,  and  the  regulator  consequently  continues  to  work  under 
these  circumstances  as  if  there  was  only  one  demi-magneto  acting. 


880 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


Electric  regulators  and  indicators. 


A 


Fig.  292. — Modification  of  the  electric-light  regulator. 


Fig.  293.— Electric  indicator  of  the  stoppage  or 
slowing  of  the  machines. 


881 


CIVIL  ENGINEERING,  ETC. 

As  to  the  lighting,  it  is  done  hy  a hand  lever  which  separates  the 
caibon  points  the  exact  distance  requisite  for  the  production  of  the 

arc  light. 

(409)  Controlling  apparatus.— The  apparatus  of  an  electric  light- 
house is  also  supplemented  by  different  instruments  to  indicate  the 
working  and  make  known  the  defects  which  may  be  produced,  viz: 

First.  A Siemens  electro-dynamometer  to  measure  the  intensity  of 

the  currents. 

Second.  An  electric  indicator  of  the  stoppages  or  slowing  of  the 
magneto-electric  machines,  by  means  of  a bell.  This  apparatus  con- 
sists of  a traveler  (Fig.  293)  moving  by  means  of  centrifugal  force* 
along  a fixed  rod  attached  at  right  angles  to  the  axle  of  the  magneto- 
electric  machine,  and  which  compresses  a spiral  spring  in  proportion 
to  the  velocity  of  rotation  given  to  the  machine. 

When  the  velocity  is  insufficient  the  spring  brings  the  moving 
piece  into  such  a position  that  it  closes  the  circuit  of  an  electric  bell. 

Third.  An  electric  signal,  showing  when  the  light  has  been  extin- 
guished. This  consists  of  an  electro-magnet  with  its  coil  in  a cir- 
cuit secondary  to  that  of  the  regulator.  If  the  light  is  extinguished 
the  principal  current  is  arrested  and  the  secondary  becomes  capable 
of  causing,  by  means  of  the  electro-magnet,  the  motion  of  a soft  iron 
rod  arranged  so  as  to  close  the  current  of  an  electric  bell.  (Fig.  294). 

Fourth.  An  alarm  serves  to  awaken  the  keeper  when  any  stoppage 
of  the  machines  takes  place. 

Cost. — The  cost  of  the  various  pieces  of  apparatus,  including  the 
optical  apparatus,  the  indicating  instruments,  three  caloric  engines, 
two  magneto-electric  machines,  etc.,  is  80,000  francs. 

M.  Barbier  constructed  the  optical  apparatus ; 301.  Sautter, 
Lemonnier  & Co.,  the  motors,  and  M.  Mdritens,  the  magneto-electric 
machines,  under  the  direction  of  31.  Emile  Bernard,  director  of  the 
liglit-liouse  service. 

Chapter  LII. — Acoustic  signals  in  connection  with  elec- 
tric LIGHT-HOUSES. 

(410)  Programme. — It  is  proposed  to  realize  in  the  new  establish- 
ments the  following  programme: 

First.  To  utilize  as  much  as  possible  the  personnel  and  machinery 
of  the  electric  light-houses  for  working  the  acoustic  signals. 

Second.  To  arrange  all  the  mechanism  so  as  to  produce  the  sounds 
when  needed. 

Third.  To  emit  these  sounds  at  a distance  from  a light-house  un- 
der the  most  favorable  conditions  to  be  heard  at  sea. 

Compressed  air  is  used  instead  of  steam,  and  all  the  apparatus  is 
united  in  the  same  building  under  one  engineer,  who  takes  charge 
of  the  electric  and  the  acoustic  apparatus,  and  the  three  caloric  en- 
gines used  to  drive  the  air-compressor. 

The  sirens  are  operated  by  compressed  air,  from  a reservoir. 

H.  Ex.  410 — VOL  ill 56 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


882 


THE  ESTABLISHMENT  OF  THE  SOUND  SIGNALS  IN  THE  ELECTRIC 
LIGHT-HOUSE  OF  BELLE  ILE  AND  BARFLEUR. 


Fig.  295  shows  the  arrangement  of  the  machinery  in  the  Belle  He 
light-house. 

Francs. 

A,  A,  A,  caloric  engines,  9 horse 

power  each 24,000 

B,  air-compressor,  20  horse  power, 

with  water  circulation  to  cool  it . 8, 000 

C,  Holmes  siren,  with  electric- 

mechanism  for  the  emission  and 
the  rythin  of  the  sounds 8, 000 

D,  D,  two  reservoirs  containing  4.5 

cubic  meters  of  compressed  air.  6,800 

EE,  two  distributing  reservoirs- 
containing  1.5  cubic  meters  ....  2, 400 

I,  motor  of  one-half  horsepower.  1,100 

K,  Gramme  dynamo  to  work  the 

sirens 1,600 

L,  shafts,  belts,  etc 5,400 

M,  M,  M,  M,  engaging  and  disen- 
gaging gear 4, 1(M) 

P,  P,  plate  iron  reservoirs 2,500 

R,  pipes  and  valves 2, 900 

Sundries % 3, 200 


Total 70,000 

S,  S,  electro-magnetic  machines. 

This  sum  includes  much  that  is 
required  for  the  light-house  itself. 
The  extra  expense  is  about  34,000 
francs,  without  including  the  cost 
of  erection. 

The  contractors  were  MM.  Saut- 
ter, Lemon nier  & Co.,  under  the 
direction  of  M.  Bourdelles,  chief  en- 
gineer of  the  light-house  service. 


Chapter  LIII. — ' The  illumina- 
tion OF  ISOLATED  BUOYS  AND 
BEACONS  BY  MEANS  OF  GASO- 
LINE. 


Fig.  295. — Plan  of  the  establishment  in  the 
light-house  at  Belle  lie. 


(411)  It  is  very  important  for  the 
security  of  navigation  that  there 
should  be  some  means  of  lighting 
economically  the  beacon  towers  on 
isolated  reefs.  This  lias  been  suc- 
cessfully accomplished  in  the  fol- 
lowing manner. 


CIVIL  ENGINEERING,  ETC.  883 

The  apparatus.  Fig.  20G  consists  of  four  burners  placed  in  the 
center  of  a dioptic  drum  with  a fixed  light  and  sheltered  by  a cylin- 
drical lantern.  This  lantern  is  glazed  below  for  a height  correspond- 
ing to  the  optical  apparatus,  and  furnished  with  every  arrangement 
requisite  for  ventilation  and  for  avoiding  the  effects  of  squalls.  Its 
upper  part  is  closed  with  plate  iron  riveted  to  uprights  built  into  the 
masonry  of  the  tower.  A door  above  the  glazing  allows  the  optical 
appaiatus  to  be  removed,  and  the  burners  replaced  or  repaired. 

(412)  The  burners  communicate  with  two  reservoirs,  each  holding 
225  liters  and  intended  to  contain  enough  gasoline  to  last  for  there 
months.  These  reservoirs  are  placed  around  the  iron  lantern,  leav- 
ing two  sectors  for  the  service.  They  are  sheltered  from  the  sun,  the 
rain,  and  the  sea,  by  an  iron  roof,  and  a cylindrical  cage,  supported 
by  a strong  steel  lattice  girder  which  allows  the  luminous  beams  to 
pass  through  the  openings.  The  girder  is  built  into  the  masonry, 
and  the  whole  construction  is  sufficiently  strong  to  resist  completely 
the  action  of  the  waves.  To  increase  this  resistance,  the  tower  is 
raised  as  much  as  possible  above  the  level  of  the  sea,  and  its  diame- 
ter at  the  top  exceeds  by  1 or  2 meters  that  of  the  iron  superstruc- 

, ture,  which  is  2 meters. 

(413)  Properties  of  petroleum  products. — Long  experience  shows 
that  all  petroleum  products  employed  in  lighting,  produce,  by  their 
decomposition  by  heat,  tar  deposits,  and  charcoal,  adhering  to  the 
orifices  of  the  burners,  which,  increasing  with  time,  reduce  more 
and  more  the  flow  of  the  fluid,  and  consequently  the  intensity  of  the 
flame. 

The  amount  of  these  deposits  diminishes,  and  the  duration  of  the 
light  increases,  as  the  product  employed  is  more  volatile  and  ap- 
proaches the  character  of  the  ethers.  Again,  the  luminous  intensity 
diminishes  as  the  essence  employed  becomes  lighter.  For  these  rea- 
sons, a gasoline  weighing  G70  grams  per  liter,  perfectly  pure  and 
rectified,  has  been  selected.  As  to  the  burners,  the  old  type  has  been 
kept.  They  are  furnished  with  a capillary  tube  giving  vent  to  the 
gasoline  vapor  which  is  projected  without  pressure  upon  a metallic 
spatula  upon  which  the  flame  rises  in  the  form  of  a butterfly.  This 
spatula  serves,  besides,  to  heat  still  more  the  gasoline  which  comes 
from  the  burner.  The  former  passes  through  a tube  communicating 
with  the  reservoirs,  and  is  tamped  with  cotton  near  the  burner. 

(414)  The  arrangement  of  the  reservoirs  constitutes  the  most  deli- 
cate portion  of  the  problem.  It  is  necessary  to  store  nearly  half  a 
cubic  meter  of  gasoline,  to  furbish  this  combustible  as  it  is  used,  to 
maintain  a constant  pressure  at  the  burner  in  order  to  have  a con- 
stant combustion,  and,  finally,  to  avoid  all  overflow  of  an  extremely 
volatile  liquid  capable  of  producing  an  explosive  mixture,  which 
might  give  rise  to  a serious  accident.  For  this  purpose  a special 
contrivance  was  adopted,  namely,  a pressure  regulator  between  each 


884 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


reservoir  and  the  burners  which  are  fed  by  it.  This  regulator  con- 
sists of  a cylindrical  floater  which  carries,  in  the  direction  of  its 
axis,  a graduated  test-glass  containing  a calculated  quantity  of  mer- 
cury, into  which  a glass  tube  plunges;  this  tube  has  a stopcock  and 
communicates  with  the  reservoir.  The  iioater  rises  with  a slight 
play  in  a receiver  united  to  the  burners  by  means  of  a tube  from  the 
bottom.  The  reservoir  cock  being  open,  the  gasoline  flows  through 
the  tube,  fills  the  test  glass,  flows  into  the  receiver,  and  raises  the 
floater.  As  the  hitter  rises,  the  reservoir  tube  sinks  gradually  into 
the  mercury  and  thus  reduces  the  flow  of  the  gasoline  until  it  ceases. 


Fig.  290.— Section  of  the  apparatus  for  lighting  beacon  towers  with  gasoline. 

At  this  moment  the  level  of  the  liquid  attains  in  the  reservoir  a 
height  of  0.30  meter  above  the  orifice  of  the  burner,  i.  e.,  the  most 
favorable  height  for  the  working  of  the  light.  Then  the  burner 
may  be  lighted  by  opening  the  burner  cocks.  The  gasoline  runs 
from  the  receiver  and  lowers  the  floater  until  the  flow  of  the  reser- 
voir equals  that  consumed  by  the  burners.  The  permanent  flow  is 
then  established,  and  the  apparatus  works  automatically  with  great 
sensitiveness,  and  maintains  regularity  of  flow,  notwithstanding  the 


885 


CIVIL  ENGINEERING,  ETC. 


thermometnc  and  barometric  variations,  whatever  may  be  the  height 
oi  the  gasoline  in  the  reservoirs. 

Repeated  experiments  have  shown  that  the  arrangements  adopted 
answer  perfectly  the  purpose  for  which  they  were  established  The 
light  has  been  kept  burning  one  hundred  and  fifty  days  and  nights 
without  changing  the  burners.  The  luminous  intensity  is  equal  to 
that  of  three  Carcel  burners  for  a group  of  four  burners.  With  the 
optical  apparatus  a light  is  obtained  nearly  equal  to  that  of  the  fifth 
order  of  Fresnel  lights. 

No  accident  has  thus  far  occurred,  and  everything  indicates  that, 
with  simple  precautions,  lights  may  be  maintained,  at  least  in  the 

beacon  towers. 

One  of  these  was  set  up  on  the  beacon  tower  near  Rd  Island  oppo- 
site the  new  port  of  La  Pallice,  and  a number  are  in  process  of  erec- 
tion. 


(415)  Cost.— The  cost  of  the  metallic  superstructure,  including 
the  optical  apparatus,  the  reservoirs,  and  all  accessories,  was  7,000 
francs.  As  to  the  cost  of  maintenance,  it  cannot  be  calculated  ' ex- 
actly; it  varies  with  circumstances;  it  maybe  approximately  esti- 
mated at  1,000  francs  per  year,  as  an  average. 

This  system  of  lighting  proposed  by  M.  Bourdelle,  chief  engineer 
of  the  light-house  service,  was  constructed  by  MM.  Barbier  & Co. 


Chapter  LIV.—  Graphic  method  of  quadrature. 

By  M.  Ed.  Colugnon,  Chief  Engineer  of  Roads  and  Bridges. 

(416)  The  following  figures,  illustrating  a new  graphical  method 
of  quadrature,  were  exhibited  in  the  pavilion  of  the  ministry  of 

public  works. 


Fig.  297. 


The  quadrature  of  a plane  area  may  be  reduced  to  the  problem  of 
finding  the  sum  of  adjoining  trapezoids  I,  II,  III  (Fig.  297),  the 
bases  of  which  are  situated  in  a right  line.  This  summation  is  easily 
made  by  the  following  method  : 


886 


UNIVERSAL  EXPOSITION  OK  1889  AT  PARIS. 


Take  the  middle  points,  1,  2,  3 of  the  upper  sides  of  the  succes- 
sive trapezoids.  Draw  the  line  1 2;  it  cuts  in  a the  ordinate  sepa- 
rating the  trapezoids  I and  II.  Reverse  this  line  1 2 end  for  end. 
The  point  « after  this  reversal  takes  the  position  (1  2),  defined  by  its 
distance  2 (1  2)  = 1 a.  It  is  easy  to  see  that  the  product  of  the  ordi- 
nate of  the  point  (1  2)  by  the  sum  A C of  the  bases  is  the  measure  of 
the  sum  of  the  areas  of  the  two  figures  I and  II. 

We  then  join  (1  2)  and  3,  which  gives  a right  line  cutting  in  /i  the 
ordinate  separating  the  surfaces  II  and  III.  On  reversing  end  for 
end  the  right  line  (1  2)  3,  and  taking  the  segment  (1  2)  (1  2 3)  =3/3; 
the  product  of  the  ordinate  of  the  point  (12  3)  by  the  sum  A D of 
the  three  bases,  will  be  equal  to  the  sum  of  the  surfaces  I.  II.  III. 

Finally  joining  (1  2 3)  and  4 and  taking  (1  2 3)  (1  2 3 4)  = 4 y we 
obtain  a point  (1  2 3 4)  situated  vertically  over  the  middle  H of  the 
total  base  A E,  and  such  that  the  product 

H (1  2 3 4)  x A E 

is  the  sum  of  the  surfaces  of  the  four  given  trapezoids. 


The  method  is  general;  it  applies  to  the  algebraic  addition  of  posi- 
tive or  negative  areas,  to  the  evaluation  of  closed  areas,  etc. 

(417)  The  consideration  of  zero  areas  is  useful  for  adding  noncon- 
tiguous trapezoids,  and  for  reducing  a rectangle  to  a given  base. 
First.  Suppose  (Fig.  298)  that  we  had  to  add  the  two  figures  I and 
III,  separated  by  a free  interval,  B C,  standing  on  the  same  line, 
A I):  we  will  consider  the  interval  B C as  a rectangle  II  with  a 
height  zero,  which  will  make  a connection  between  the  surfaces  I 
and  III.  Applying  the  method  to  the  three  trapezoids  I,  II,  III,  we 
arrive  at  a final  point  (1  2 3),  and  the  product 

(1  2 3)  H x A D 

is  the  required  area. 

(418)  Second.  To  change  a rectangle,  A B C D,  into  an  equivalent 
rectangle,  which  has  for  base  a given  length,  A,  E.  We  will  con- 
sider the  required  rectangle  as  the  sum  of  the  rectangle  A B C D 
(Fig.  299),  and  a rectangle  having  zero  for  height,  and  B E for  base. 
We  therefore  take  the  middle  points,  1 and  2,  of  the  upper  sides  of 
these  rectangles;  we  join  1 and  2,  the  line  1 2 cuts  in  a the  ordinate, 


f 

i 


CIVIL  ENGINEERING,  ETC. 


8sr 


which  separates  the  two  surfaces,  and  taking  1 (1  2)  = 2 a,  we  have 
at  the  point  (12)  the  middle  of  the  upper  side  of  the  rectangle, 
A E F G,  which  has  for  base  A E,  and  which  is  equivalent  to  the  given 
rectangle.  The  construction  avoids  the  last  multiplication  which 
would  be  necessary  to  compute  the  total  area.  We  may  take  the 


Fig.  5299. 


base,  A E,  so  as  to  render  this  last  operation  very  rapid.  It  is  suf- 
ficient to  make,  for  example,  A E = 1 meter,  or  equal  10  meters  or 
100  meters,  etc. 

(419)  The  method  applies  to  the  computation  of  the  surfaces  of 
cross  sections,  to  the  tracing  of  longitudinal  sections  along  a line,  for 
balancing  excavations  and  embankments,  and  for  the  determination 
of  the  mean  of  given  numbers  without  seeking  beforehand  the  total. 


Fig.  300. 

Finally,  it  applies  to  the  quadrature  of  curves  with  the  same  degree 
of  approximation  as  that  given  by  Simpson’s  rule. 

Divide  the  base  A B of  the  area  to  compute  into  an  even  number 
of  equal  parts,  in  eight  parts,  for  example  (Fig.  300),  at  the  points 
1,  2, ...  7;  erect  ordinates  at  the  points  of  division,  then  draw  the 
chords  A' m,  n m,  n p,  p B',  by  joining  the  successive  points  of  the 
curve  situated  upon  the  even  ordinates.  Take  the  points  a,  b , c,  cl, 
on  the  deflections  of  the  segments  comprised  between  the  curve  and 
the  chords  at  two-thirds  of  these  deflections  starting  from  the  chord. 


UNIVERSAL  EXPOSITION  OF  1889  AT  PARIS. 


888 

It  only  remains  to  join  a and  b,  which  gives  the  point  (a  b)  upon  the 
ordinate  (2);  to  join  (a  b)  and  c,  which  gives  the  point  (o  b c)  on  the 
ordinate  (3);  to  join  (a  b e)  and  d,  which  gives  the  point  (o  b c d)  upon 
the  central  ordinate  of  the  curve.  The  required  area  is  the  product 

A B x 4 (abed). 

The  equidistance  of  the  ordinates  has  avoided  the  necessity  of 
reversing  end  for  end  the  successive  joining  lines,  the  construction 
being  thus  considerably  simplified. 


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